Question

The angle measures 22°, 62°, 118°, and 158° are written on slips of paper. You choose two slips of paper at random.

What is the probability that the angle measures are supplementary? Enter your answer as a fraction.


P =

Answer 1

Answer: 1/3

There are C(4,2) = 6 ways to choose a pair of numbers. Only 2 of those pairs are supplementary measures {22, 158} and {62, 118}. The probability is 2/6 = 1/3.