Question

The manager of a grocery store estimates that 74% of customers will make a purchase.



Part A: How many customers should a cashier expect until he finds a customer that makes a purchase?



Part B: What is the probability that a cashier helps 3 customers until he finds the first person to make a purchase?

Answer 1

Answer:

A :  Per 100 people, cashier should expect 26 customer until he finds a costumer that makes a purchase.

B:   The probability is 1/4

Step-by-step explanation:

The estimated chance of a customer making a purchase  = 74%

So, if a TOTAL of 100 people visit the grocery store on any random day,

then 74 % of customers  

= 74% of 100

= 74 people will make purchases.

⇒ Out of total 100 people visiting, 74 people  will make a purchase.

So, the number of people NOT making a purchase = 100 - 74 = 26

⇒ Out of total 100 people visiting, 26 people  will NOT make a purchase.

Also, 26 = 26% of 100

Part A :

So, in order to make a purchase, cashier should expect 26% of customers because the percentage of NOT purchasing is 26%.

Hence, per 100 people, cashier should expect 26 customer until he finds a costumer that makes a purchase.

Part B :

The percentage of customer making a purchase = 74%

The percentage of people NOT making a purchase  = 26%

So, for every 3 customer making a purchase there is a 1 person NOT making  a purchase.

So, the probability is 1/4

Answer 2

Part A) 

1.35 customers until the cashier should expect to find a customer that makes a purchase.

1 ➗ 0.74 = 1.35

Part B)

0.013 is the probability that the cashier helps 3 customers until he finds the first person to make a purchase.

(1 - 0.74)3 x 0.74 = 0.013