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Flashcards in Word Problems And Stats Deck (11)
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1

"AND" probabilities...

...use the words AND or BOTH
...happen IN A ROW
...happen AT THE SAME TIME

2

"OR" probabilities...

...use the word OR
...use the phrase AT LEAST

3

Ask at the start of every OR question

Can both events occur?

4

OR probabilities:
If the answer is YES - the events can happen at the same time.

...This means the events are INDEPENDENT.

(1) add the probabilities that either happens
(2) subtract the probability that BOTH event occur

5

Complements

Determine the probability of the opposite of what you're looking for, and subtract it from 1 to get what you're looking for

6

"At Least Once" shortcut

Odds of an Event + Odds of its Complement = 1

At least once = 1-Never

7

Rate problems

Rate X Quantity (e.g. Time) = Work (or Distance)

8

Proportion rate problem

LABEL each item within the proportion. Then cross-multiply to solve the equation.

But be careful of inverse relationships. In these cases, set the products of the quantities equal to each other and solve.

9

1 kilometre = how many meters?

1,000 meters

10

1 meter = how many centimetres?

100 cm

11

1 centimetre = how many millimetres?

100 millimetres