Question

A stoplight has the following cycle: green for 90 seconds, yellow for 10 seconds, and red for 60 seconds. What is the probability that the light will be red for a car approaching the stoplight?

Answer 1

Total cycle lasts:
90s+10s+60s=160s

Red light lasts 60s.

To find the probability we divide the number that represents state that fits to our condition with total number:
60 / 160 = 3 / 8
Probability that car will meet red light is 3/8 or 37.5%.