What is the probability of choosing a boy or an A student?

Question

In a science class of twenty-eight students, 12 boys and 16 are girls. On a unit test, 4 boys and 10 girls made an A grade. A student is chosen at random from the class. What is the probability of choosing a boy or an A student?

Answer 1

One way to solve this problem is to consider the COMPLEMENT of "Choose a boy OR an A student". The only way to not choose "a boy OR an A student" is to choose a girl who didn't get an A. Since there are 10 girls who got A's, that means that there were 6 girls who didn't get an A.

This means that the probability of choose a girl who didn't get an A is 6/28, which reduces to 3/14. This means that the probability of choosing a boy OR an A student is 1 - 3/14, or 11/14.

There are other ways to solve this problem, but this is one fairly simple way to find the solution.

Good luck to you,

JMJ