Flashcards in Hashmat teaches Deck (50)

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1

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GMAT Set 3 Qs.4 Roots??

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Stuck on this one. would appreciate it if someone can assist

Qs. Root {(2*root 63)-2/(8 + (3*root 7))}

A. 8 + (3* root 7)

B. 4 + (3* root 7)

C. 8

D. 4

E. root 7

Thanks

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IMO D

I got the answer. there was a misprint in the question. read the equation as

Root {(2*root 63) + 2/(8 + (3*root 7))}.. the mistake is the positive sign. the question has mistakently been written as negative. the correct question would be with the positive sign

here is how i solved it ....eventually

realize that 3* root 7 = root 63

now let root 63 be A then the equation would read

root {2*{A+1/(8+A)} ....taking 2 common

root {2*{[A*(8+A)+1]/(8+A)}

root {2*{[8A+A^2 +1]/(8+A)

now put A = 3*root 7

then 8A+A^2-1 = 8*3*root 7 + 9*7 +1

= 8*3*root 7 + 63 +1 = 8*3*root7 +64

take 8 common 8(8+ 3* root 7)

put 3*root 7 = A

then = 8(8+A)

put the expression back in the main equation we get

root {2*{8*[8+A]/[8+A]}}

= root 8*2 = root 16 = 4 hence D is the answer

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Urban Class room

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Uninformed about students experience in urban classrooms, critics often condemnschool's performance gauged by an index, such as standardized test scores, that are called objective and can be quantified and overlook less measurable progress such as that in higher learning

A -

B an index, such as standardized test scores, that are called objective and can be quantified and overlook less measurable progress such as what is mde

c. an index, suc as standardized test scores that is called objective and can b equantified and overlook less measureable progress, such as what is made

d. a so-called objective indes, such as standardized test scores, tha can be quantified and over look less measurable progress, such as what is made

e. a so called objective index, such as standardized test scores, taht can be quantified and overlook less measurable progress, such as that

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So many typos...

Please confirm the options...

Uninformed about students experience in urban classrooms, critics often condemn school's performance gauged by an index, such as standardized test scores, that are called objective and can be quantified and overlook less measurable progress such as that in higher learning.

A. an index, such as standardized test scores, that are called objective and can be quantified and overlook less measurable progress such as that

B. an index, such as standardized test scores, that are called objective and can be quantified and overlook less measurable progress such as what is made

C. an index, such as standardized test scores (,) that is called objective and can be quantified and overlook less measureable progress, such as what is made

D. a so-called objective index, such as standardized test scores, that can be quantified and over look less measurable progress, such as what is made E. a so called objective index, such as standardized test scores, that can be quantified and overlook less measurable progress, such as that

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From 1982 to 1987

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1. From 1982 to 1987 sales of new small boats increased between five and ten percent annually.

(A) From 1982 to 1987 sales of new small boats increased between five and ten percent annually.

(B) Five to ten percent is the annual increase in sales of new small boats in the years 1982 to 1987.

(C) Sales of new small boats have increased annually five and ten percent in the years 1982 to 1987.

(D) Annually an increase of five to ten percent has occurred between 1982 and 1987 in the sales of new small boats

(E) Occurring from 1982 to 1987 was an annual increase of five and ten percent in the sales of new small boats.

Spoiler:

SPOILER: A

Why????

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IMO B.

A--> from A to B increase must be from X to Y and not and.

B--> correct

C-->five and ten percent...wrong

D-->increase of A to B occured between X and Y...should be from X to Y

E-->flawed as explained above.

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Set 3 Q36

If a, b, c, and d are positive integers, is (a/b) (c/d) > c/b?

(1) c > b

(2) a > d

Official Answer is (B) but I cannot figure out y..

Thanks for thy help!

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Good post? |

IMO B

ac/bd = a/d * c/b > c/b

therefore a/d > 1. since a,b,c,d are postive integers therefore the expression must be greater than zero. in statment 2 a > d therefore a/d must be greater than 1 Hence statement II is sufficient.

Hence B

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boy : girls (ratio)

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If the ratio of boys to girls attending school S in 1980 was 1/2, what was the ratio of boys to girls attending school S in 1981?

(1) 50 more boys were attending school S in 1981 than in 1980

(2) 50 more girls were attending school S in 1981 than in 1980.

Official Answer is E

pls explain

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It should be E

Let B and G be the no. of boys in 1980

In 1980 the ratio B/G = 1/2

From 1. In 1981 no. of boys is B+50 --> Insuff as no. of girls not known

From 2. In 1981 no. of girls is G+50 --> Insuff as no. of boys not known

From 1 & 2

Ratio -> (B+50)/(G+50). Since we don't know the values for B and G we cannot find the ratio. --> Insuff

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DS Quadrilateral

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Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

(1) Two of the interior angles of ABCD are right angles.

(2) The degree measure of angle ABC is twice the degree measure of angle BCD.

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Good post? |

IMO E too

Set No 14 says that the Official Answer is C. but i like E best....

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1000sc: 45

According to his own account, Frederic-Auguste Bartholdi, the sculptor of the Statue of Liberty, modeled the face of the statue like his mother's and the body like his wife's.

(A) modeled the face of the statue like his mother's and the body like his wife's

(B) modeled the face of the statue after that of his mother and the body after that of his wife

(C) modeled the face of the statue like his mother and the body like his wife

(D) made the face of the statue after his mother and the body after his wife

(E) made the face of the statue look like his mother and the body look like his wife

Can someone explain ?

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IMO B

Modelled after is the correct idiom

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percentage ..

Martha bought an armchair and a coffee table at an auction and sold both items at her store. Her gross profit from the purchase and sale of the armchair was what percent greater than her gross profit from the purchase and sale of coffee table ?

(1) Martha paid 10% more for the armchair than for the coffee table

(2) Martha sold the armchair for 20 percent more than she sold the coffee table

Friends, I opted for C. But that was not the Official Answer. Please help.

Thanks,

Arun B

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Good post? Yes | No

I've found that the easiest way to solve these is to do the following:

1. What are we trying to solve?

In this problem, we are looking for the percent diffence between the profit of the armchair and the profit of the table.

2. What formula(s) do we need?

We need the profit forumla {P = R - C} and the percentage difference or increase forumla {(x - y)/y * 100} (note that x is the bigger number)

Combining these two, let's create a formula to directly answer the question:

Pa = Ra - Ca

Pt = Rt - Ct

% = (Pa - Pt)/Pt

3. Now we look at each part individually and plug the info into the equation to see if it is solved.

(1) "Martha paid 10% more for the armchair than for the coffee table"

So, Ca = 1.1 * Ct

Clearly this does not give us a value for Pa or Pt, so it is not sufficient.

(2) Martha sold the armchair for 20 percent more than she sold the coffee table

So, Ra = 1.2 * Rt

Alone, this also clearly does not give us a value for Pa or Pt.

4. Now the big question: will both together get the job done?

Pa = Ra - Ca

Pt = Rt - Ct

Now we substitute the first equation with what we were given, so:

Pa = 1.2*Rt - 1.1*Ct

Finally, let's see if that's enough:

% = (Pa-Pt)/Pt

% = [(1.2*Rt - 1.1*Ct) - (Rt - Ct)]/(Rt-Ct)

% = (.2*Rt - .1*Ct)/(Rt-Ct)

Close but no cigar! Both together are NOT sufficient.

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Q1:

A grocer has 400 pounds of coffee in stock, 20 percent of which is decaffeinated. If the grocer buys another 100 pounds of coffee of which 60 percent is decaffeinated, what percent, by weight, of the grocer’s stock of coffee is decaffeinated?

A. 28%

B. 30%

C. 32%

D. 34%

E. 40%

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IMO A

20*400/100 = 80 pounds of decaf in old mixture

60*100/100 = 60 pounds of decaf in new mixture

Total Mixture = 400+100 = 500 pounds

Total Decaf = 60 +80 = 140 pounds

Total Decaf / Total Mixture = 140/500 = 28%

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Q2:

If 2 different representatives are to be selected at random from a group of 10 employees and if p is the probability that both representatives selected will be women, is p > 1/2?

(1) More than 1/2 of the 10 employees are women.

(2) The probability that both representatives selected will be men is less than 1/10.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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Courtesy of GMAT Help’s explanation

IHO E

P(both women) > 1/2 ?

10 employees

Total possibilities = 10c2 = 45

=> nc2/10c2 > 1/2 ?

=> nc2 > 45/2 ?

=> nc2 > 22.5 ?

=> n >= 8 ?

Stmt 1:

Number of female employees > 5

=> n can be 6 or 9 which will give different probability..

Insufficient

Stmt 2:

P(both men) mc2/10c2 mc2 m number of females >= 7

Insufficient as we need n >= 8

Combining together, n can still be >= 7

Insufficient

Ans E.

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Q3:

If the population of a certain country is 120,256,000 and its land area is 2,998,000 square kilometers, then the population per square kilometer is closest to which of the following?

A. 4

B. 6

C. 20

D. 40

E. 60

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IMO D

120,256,000 = 120,000,000

2,998,000 = 3,000,000

Therefore 120,000,000/3,000,000 = 40

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Q4:

4.8*10^9/(1.6)10^3 =

A. 30(105)

B. [3(10)]6

C. 305

D. 30(106)

E. 3(1012)

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IMO A

4.8/1.6* 10^(9-3) = 3 * 10^6 = 30 * 10^5

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Q5:

If vmt ≠ 0, is v2m3t-4 > 0?

(1) m > v2

(2) m > t-4

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO D

V^2 and t^(-4) will always be positive i.e greater than zero.

So we need to check if m is greater than zero or not i.e m is not negative.

Both statements show that m will be positive i.e it is greater than square of a number.

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Q6:

B C

xº

yº zº

A D

In the figure shown, line segment AD is parallel to line segment BC. What is the value of x?

(1) y = 50

(2) z = 40

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO A

If y = 50 then x is 50 as per the rule of parallel lines and adjacent angles.

Statement II is not sufficient as the angle next to x is not known.

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Q7:

A certain university will select 1 of 7 candidates eligible to fill a position in the mathematics department and 2 of 10 candidates eligible to fill 2 identical positions in the computer science department. If none of the candidates is eligible for a position in both departments, how many different sets of 3 candidates are there to fill the 3 positions?

A. 42

B. 70

C. 140

D. 165

E. 315

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IMO E

7C1*10C2 = 315

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Q8:

The points R, T, and U lie on a circle that has radius 4. If the length of arc RTU is 34π, what is the length of line segment RU?

A. 34

B. 38

C. 3

D. 4

E. 6

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IMO D

Let x be the angle of the arc then x/360 * 2pi r = 34pi

Therefore x = 60

Now let y be the other two angles then 2y+60 = 180 therefore y = 60 hence the triangle is an equilateral triangle

So all three sides are equal. If you have drawn a diagram you can see that the line RU will be 4.

The triangle that I have drawn joins points RU and O where O is the origin of the triangle.

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Q9:

For all integers n, the function f is defined by f (n) = an, where a is a constant. What is the value of f (1)?

(1) f (2) = 100

(2) f (3) = -1,000

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO B

Statement I is not sufficient because we donot know whether a is +10 or – 10

Statement II clarifies that a = -10 therefore F(1) = -10

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Q10:

What is the value of (x - y)4?

(1) The product of x and y is 7.

(2) x and y are integers.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO C

Statement I is not sufficient because we donot know whether x and y are integers or fractions

Statement II says nothing about the value of x and y therefore it is also insufficient.

Combining the two statements we get that x and y must be 7, 1. The value of x-y will vary depending on whether x is equal to 7 or y is equal to 7.

Hence the answer for x-y could be 6 or -6. But even power takes care of any negative sign. Therefore combining the two statements is sufficient hence C

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Q11:

Mary persuaded n friends to donate $500 each to her election campaign, and then each of these n friends persuaded n more people to donate $500 each to Mary’s campaign. If no one donated more than once and if there were no other donations, what was the value of n?

(1) The first n people donated 1/16 of the total amount donated.

(2) The total amount donated was $120,000.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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Courtesy of Man on the Moon

IHO D

For 1)

total amount = (n + n^2)500

i) we have

500n = 1/16((n + n^2)500)

we get,

n^2 - 15n = 0

n(n-15) = 0

I assume n cant be 0, as it denotes first set of people.

If I can assume this, then this is sufficient.

ii) suff too

Hence D

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Q12:

When n liters of fuel was added to a tank that was already 1/3 full, the tank was filled to 7/9 of its capacity. In terms of n, what is the capacity of the tank, in liters?

A. 10/9 n

B. 4/3 n

C. 3/2 n

D. 9/4 n

E. 7/3 n

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IMO D

N = 7x/9 –x/3 where x is the total capacity of the tank

N = 4/9x then x = 9n/4

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Q13:

If n is a positive integer, what is the remainder when 38n+3 + 2 is divided by 5?

A. 0

B. 1

C. 2

D. 3

E. 4

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IMO E

Plug in 1,2,3 as values of n we get 8n+3 = 11, 19, 27

Now multiples of 3 have unit digits equal to 3,9,7,1,3,9,7,1….

The llth power of 3 would have 7 as a unit digit and so will 19th and 27th

Therefore 7+2 = 9 hence the total expression would have a unit digit equal to 9 dividing by 5 would result in a remainder of 4 Hence E is the answer

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Q14:

Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?

A. 1/15

B. 1/5

C. 4/15

D. 1/3

E. 2/5

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IMO B

Let the total number of students be 100 then 50 students are first year and 50 students are second year students

Now 4/5 of 50 = 40 students are first year students and have not declard a major whereas 10 students are first year students and have declared a major (i.e 50 – 40 = 10)

Now second year students who have declared a major are 3 times the first year students who have declared a major therefore =3 * 10 = 30

Therefore the second year students who have not declared a major are 50 – 30 = 20

Hence 20% have not declared a major and are 2nd year students. (i.e 1/5) hence b is the answer.

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Q15:

If p is the product of the integers from 1 to 30, inclusive, what is the greatest integer k for which 3k is a factor of p?

A. 10

B. 12

C. 14

D. 16

E. 18

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IMO C

Multiples of 3 are 3,6,9,12,15,18,21,24,27,30

That is 10 powers of 3 but 9,18,27 have more powers of 3 i.e 9 = 3*3, 18 = 3*3*2 and 27=3*3*3

Count the additional 3s there would be four therefore the answer must be 14.

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Q16:

If x and y are positive, is x3 > y?

(1) root x > y

(2) x > y

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO C

Statement I root x > y. now two possibilities could exist that x is less than y but both are fractions therefore its root is more than y for example let x = 1/4 and y = 1/3. now root x = 1/2 which is more than y.

another possibility is that x is larger than y and is so large that even its root is greater than y for example let x = 16 and y = 2 therefore root 16 = 4 therefore it is greater than y.

Statement II clarifies that point. It says that x is greater than y. This rules out the first possibility becasuse the premise of the possbility is that x is less than y and both are fractions. Hence that leaves us with possibility that x > y therefore x^3 must be greater than y. BTW it has already been pointed out that both x and y are positive integers.

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Q17:

If x, y, and k are positive numbers such that (yxx+)(10) + (yxy+)(20) = k and if x

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Courtesy of ravindraiit

IHO D

(x/(x+y))(10) + (y/(x+y))(20) = k

=> [10(x+y)+10y]/(x+y) = k

=> y/(x+y)= (k-10)/10 -- (a)

x x+y y/x+y > (1/2)

(a) => (k-10)/10 > (1/2) => k>15

also y/(x+y) (k-10)/10 k

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Q18:

What is the value of the integer k?

(1) k + 3 > 0

(2) k4 ≤ 0

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient

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IMO B

The only number whose square is equal to zero is zero. Hence K = 0 Hence statement I is sufficient.

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Q19:

Each of the 30 boxes in a certain shipment weighs either 10 pounds or 20 pounds, and average (arithmetic mean) weight of the boxes in the shipment is 18 pounds. If the average weight of the boxes in the shipment is to be reduced to 14 pounds by removing some of the 20-pound boxes, how many 20-pound boxes must be removed?

A. 4

B. 6

C. 10

D. 20

E. 24

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IMO D

Let x be the number of 10 pound boxes and y be the number of 20 pound boxes then

10x+20y/30 = 18

But x+y = 30 solve for x we get x = 6 and y = 24

Now let A be the number of 20 pound boxes left then

(10*6 + 20A)/(6+A) = 14 solve for A we get A = 4

Since there were initially 24 boxes and now there are 4 so 20 boxes would have to be removed

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Q20:

Tom, Jane, and Sue each purchased a new house. The average (arithmetic mean) price of the three houses was $120,000. What was the median price of the three houses?

(1) The price of Tom’s house was $110,000.

(2) The price of Jane’s house was $120,000.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO B

B is sufficient on the grounds that the other two values would have to be either equal to 120,000 or one value would have to be greater than 120,000 and one value would be less. In either cash the median of the data would remain 120,000. hence B.

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Q21:

The results of a certain experiment included 6 data values that were all multiples of the same number c, namely, c, 8c, 2c, 5c, 4c, and 4c. Was the average (arithmetic mean) of the 6 data values greater than 8?

(1) c 2

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

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IMO B

C+8C+2C+5C+4C+4C = 24C = Total Sum

Average = 24C/6 = 4C.

Hence the value would be equal to 8 if C = 2. Statement I says that C can be less than 2 whereas statement II is sufficient Hence B

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