Question

Conditional probability: A teacher gave his class two quizzes; 80% of the class passed the first quiz, but only 60% of the class passed both quizzes. What percent of those who passed the first quiz also passed the second quiz?

Answer 1

let A=first quiz is passed
let B=second quiz is passed
we then have that the probability of the second quiz being passed, given that the first is passed is\[P(B|A)=\frac{P(A\cap B)}{P(A)}\]

Answer 2

Right, so 75% passed both quizzes

Answer 3

well, no, it says in the problem that 60% passed both quizzes

Answer 4

pardon me, 75% who passed the first quiz also passed the second

Answer 5

correct :)

Answer 6

Thanks a bunch!

Answer 7

welcome!