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If a bottle is to be selected at random

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If a bottle is to be selected at random

by BTGmoderatorDC » Thu Dec 21, 2017 5:37 am
If a bottle is to be selected at random from a certain collection of bottles, what is the probability that the bottle will be defective?

(1) The ratio of the number of bottles in the collection that are defective to the number that are not defective is 3:500.
(2) The collection contains 3,521 bottles.

What's the best way to determine whether statement 1 is sufficient?

OA A
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Source: — Data Sufficiency |
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by DavidG@VeritasPrep » Thu Dec 21, 2017 5:16 pm
lheiannie07 wrote:If a bottle is to be selected at random from a certain collection of bottles, what is the probability that the bottle will be defective?

(1) The ratio of the number of bottles in the collection that are defective to the number that are not defective is 3:500.
(2) The collection contains 3,521 bottles.

What's the best way to determine whether statement 1 is sufficient?

OA A
P(Choosing a defective bottle) = # Defective bottles/# Total Bottles

Statement 1:
# Defective Bottles: 3x
# Non-defective Bottles: 500x
# Total Bottles: 3x + 500x = 503x

P(Choosing a defective bottle) = 3x/503x = 3/503. Because we can get a definitive unique value, we know this statement alone is sufficient.

Statement 2: Tells us nothing about the number of defective bottles. Not Sufficient

The answer is A
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