It is estimated that 78% of drivers use their turn signal. How many people should a police officer expect to pull over until she finds a driver not using the turn signal?

5

3

4

2

6

5 people

Explanation:

Given

Let P =Percentage of people using signal

P = 78%

Let Q = Percentage of people not using signal

P + Q = 1 Make Q the subject of formula

Q = 1 - 78%

Q = 1 - 0.78

Q = 0.22

The expected number of people is calculated as 1/Q

= 1/0.22

= 4.54

= 5 Approximated

Hence, the expected number of people a police officer expects to pull over until she finds a driver not using the turn signal is 5