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A teacher gave her class two tests. 40% of the class passed both tests and 65% of the class passed the first test. Find the probability of the student who passed the second test given that he or she passed the first test.Instruction: Answer with 4 decimal places

User Grimgrom
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Let A = the event of passing the first test

Let B = the event of passing the second test

We are given:

P(A and B) = 40% = 0.40

P(A) = 65% = 0.65

And we find P(B | A)

Using the formula for conditional probability, we have:


P(B|A)=\frac{P(A\text{ and B)}}{P(A)}

Then, solve:


P(B|A)=(0.40)/(0.65)=0.6154

Answer: The probability is 0.6154

User Rooneyl
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