Question

Ms. Tucker travels through two intersections with traffic lights as she drives to the market. The traffic lights operate independently. The probability that both lights will be red when she reaches them is 0.22. The probability that the first light will be red and the second light will not be red is 0.33. What is the probability that the second light will be red when she reaches it?

a. 0.40.
b. 0.45.
c. 0.50.
d. 0.55.
e. 0.60

Answer 1

b. 0.45.

Explanation:

The total possible outcome of a probability is 1

Given;

Probability that both lights will be red when she reaches them = 0.22

Probability that the first light will be red and the second light will not be red = 0.33

Probability that the second light will be red when she reaches it = x

These are all the possible outcomes, therefore

0.22 + 0.33 + x = 1

0.55 + x = 1

x = 1 - 0.55

x = 0.45

Option b