A gumball machine has just been filled with 50 black, 150 white, 100 red and 100 yellow gum balls that have been thoroughly mixed. Sue and Jim, each, purchased one gumball. What is the likelihood both Sue and Jim get red gumballs?
A) 0.50
B) 0.062
C) 0.33
D) 0.75

Question

Quizplus · Accepted Answer

The probability of Sue getting a red gumball is 100/400 = 0.25. 
Assuming she gets a red gumball, there would be 99 red gumballs left out of 399. 
The probability of Jim getting a red gumball, given that Sue already got one, is 99/399 = 0.248. 
The probability of both events happening is the product of each individual probability: 
0.25 x 0.248 = 0.062. 
Therefore, the likelihood of both Sue and Jim getting red gumballs is 0.062 or approximately 6.2%. Thus, the best choice is B.

A Gumball Machine Has Just Been Filled with 50 Black