If you select a student at random, what is the probability that the student made an A or failed the test?

Question

A class of 22 students take a statistics exam. Four students make an A, 3 students make a B, 6 students make a C, 2 students make a D. The rest of the students fail. If you select a student at random, what is the probability that the student made an A or failed the test?
Answer: 0.50

 

Help me show work that the answer is 0.50

 

Answer 1

P(A ∨ B) = P(A) + P(B)

4/22 + 7/22

11/22

1/2

0.50