Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

A college Calculus 1 course with 15 (20) who have (had) some(none) calculus in high school & probability of 3/10 (1/10) of making an "A" in Calculus 1. Some student earns "A", what is the probability of said student had some calculus in high school?

share|improve this question

1 Answer 1

What information do we have?

P(Had Calc) = 15/35
P(Gets A | Had Calc) = 3/10
P(Gets A | Not Had Calc) = 1/10

So we can use P(A|B) = P(B|A)*P(A)/P(B) like so:

P(Had Calc | Gets A) = P(Gets A | Had Calc) * P(Had Calc) / P(Gets A)

We still need P(Gets A), but I'm sure you can figure that out.

share|improve this answer
    
Do you mind walking me thru this problem to make sure I got the correct answer? –  kimj Sep 29 '12 at 20:51

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.