Question

A computer program consists of two blocks written independently by two different programmers.the first block has an error with probability 0.2. the second block has an errorwith probability 0.3. if the program returns an error, what is the probability that there isan error in both blocks?

Answer 1

The correct answer is:

0.06.

Explanation:

The probabilities of the first block having an error and the second block having an error are independent; one block having an error does not affect the probability of the second block having an error.

Since they are independent, to find the probability of both occurring, we simply multiply the probabilities:

0.2(0.3) = 0.06.

Answer 2

To work out the probability of both errors occuring, simply multiply the probability of the first error by the probability of the second error. Therefore the probability of both errors occurring is 0.2 * 0.3  =  0.06.