Question

The table below shows the amount of time a light stays green, red, and yellow (for one cycle) during the day and during the night. Day Night Light is green 2 minutes 3 minutes Light is red 3 minutes 4 minutes Light is yellow 20 seconds 30 seconds Is it more likely for you to have to wait at red light during the day or at night? How much more likely?

Answer 1

We are given that the amount of time for a given color is:

A.    Day

Green = 2 min

Red = 3 min

Yellow = 20 sec = 0.333 min

Total day cycle time= 5.33 min

B.      Night

Green = 3 min

Red = 4 min

Yellow = 30 sec = 0.5 min

Total night cycle time= 7.5 min

 

We calculate for the probabilities of waiting at red for day and night:

Pday= 3 min/5.33 min= 0.5625

Pnight= 4 min/7.5 min= 0.5333

Pdifference= 0.02917 = 2.92%

Therefore it is more likely to wait at red during day time by 2.92%.