Question

A TRAFFIC LIGHT IS RED FOR 38 SECONDS YELLOW FOR 10 SECONDS AND GREEN FOR ONE MINUTE AND TWELVE SEONDS. IN A CONSTANTLY REPEATING CYCLE, WHAT IS THE PROBABILITY THAT AT THE MOMENT A PASSING PEDESTRIAN GLANCES AT IT, THE LIGHT WILL BE GREEN

Answer 1

The chance is 3/5 that the light will be green.

Added together the total seconds for the traffic light to complete the cycle is 120 (38+72 (1 min and 12 sec) +10.

And the green light proportion is: 72/120

We simplify by dividing by 12, which is a factor and we get: 6/10 that simplifies to 3/5.

Hope this helps!