You are performing two chemistry experiments.

Question

The probability that both experiments are successful is 22%. If the first experiment is successful, the probability that the second experiment is also successful is 31%. What is the probability that the first experiment is successful?

A. 70.97%

B. 62.56%

C. 58.99%

D. 67.81%

Answer 1

Let event A = 1st experiment successful

Let event B = 2nd experiment successful

P(B|A) = 0.31

P(A and B) = 0.22

Probability Formula:

P(B|A) = P(A and B)/P(A)

0.31 = 0.22/P(A)

P(A) = 0.22/0.31 = 0.71