# Can you find out the percentage of those students who passes the first test and also passed the second test ?

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A chemistry teacher took exam of his students. Out of the total students, 25% of the students passed both the tests included in the exam. However, only 42% were able to clear the first test.

Can you find out the percentage of those students who passes the first test and also passed the second test ?

posted Jul 4, 2014
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## 1 Answer

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The formula for conditional probability:
P (Second/First) = P (First and Second)/ P (First)
= 0.25/0.42
=0.60
=60%"

answer Jul 4, 2014

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