A box contains 35 white balls 75 red balls and 45 black ball

A box contains 35 white balls, 75 red balls, and 45 black balls. If Nikki picks out a ball at random, what is the probability that the ball will be white or black?

D.

Solution

C. Probability = number of favorable outcomes/number of possible outcomes. In this problem, the number of favorable outcomes is a combination of white and black balls or 35 + 45 = 80. The number of possible outcomes is 35 + 75 + 45 = 155. So substituting into the formula, the probability is 80/155 or 16/31