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Probability

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by BTGmoderatorRO » Sun Sep 10, 2017 2:22 pm
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red ?

a. 1/25
b. 1/12
c. 1/7
d. 1/5
e. 1/3

correct option is B
Which approach did you use to solve this and how best can option C be recommended as the answer
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Source: — Problem Solving |

by [email protected] » Sun Sep 10, 2017 3:21 pm
Hi Roland2rule,

This question is an example of a fairly straight-forward probability question.

Probability = (# of ways that give us what we "want")/(Total # of ways possible.

Here, we have a total of 25+100+175 = 300 blocks and 25 of those blocks are red. Thus, the probability of randomly pulling one red block from that group is...

25/300 = 1/12

Final Answer: B

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
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Re: Probability

by Scott@TargetTestPrep » Sun Feb 02, 2020 2:03 pm
BTGmoderatorRO wrote:
Sun Sep 10, 2017 2:22 pm
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red ?

a. 1/25
b. 1/12
c. 1/7
d. 1/5
e. 1/3

correct option is B
Which approach did you use to solve this and how best can option C be recommended as the answer
The box contains 25 + 100 + 175 = 300 blocks. Since there are 25 red blocks, the probability of picking one red block out of the box is 25/300 = 1/12.

Answer: B

Scott Woodbury-Stewart
Founder and CEO
[email protected]

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