Question

At a store, customers are randomly selected to participate in a survey. On Friday, there were 500 customers at the store. Of those, 90 were selected to participate in the survey. On Saturday, the store manager expects 700 customers in the store. If the probability of being selected to participate in a survey on Saturday is the same as it was on Friday, how many customers will be selected to participate in the survey on Saturday?

Answer 1

The probability of being selected on Friday is :

Probability = no of outcomes / total number of possible outcomes.

P(S) = probability of selection = 90 / 500
= 9/50

This probability is equal to probability of selection on Saturday.

Total expected customers = 700

Total selected = 9/50 of 700

9 / 50 × 700 = 126 customers.

Answer 2

Solution :-

This is a ratio and proportion problem.

90 customers selected out of 500 is the same as how many out of 700.

⇒ 500 : 90 : : 700 : x

⇒ 500x = 700*90
 
⇒ 500x = 63000

⇒ x = 63000/500

⇒ x = 126

So, 126 customers will be selected to participate in the survey on Saturday.

Answer.