MathDB

10

Part of 1999 AMC 8

Problems(1)

1999 #10

Source:

6/17/2011
A complete cycle of a traffic light takes 60 seconds. During each cycle the light is green for 25 seconds, yellow for 5 seconds, and red for 30 seconds. At a randomly chosen time, what is the probability that the light will NOT be green?
(A) 14(B) 13(C) 512(D) 12(E) 712 \text{(A)}\ \frac{1}{4}\qquad\text{(B)}\ \frac{1}{3}\qquad\text{(C)}\ \frac{5}{12}\qquad\text{(D)}\ \frac{1}{2}\qquad\text{(E)}\ \frac{7}{12}
probability