Question

If a customer at a particular grocery store uses coupons, there is a 50% probability that the customer will pay with a debit card. Thirty percent of customers use coupons and 35% of customers pay with debit cards. Given that a customer pays with a debit card, the probability that the same customer uses coupons is ________. 0.22 0.43 0.60 0.72

Answer 1

0.43.

Explanation:

The probability that the customer will pay with debit card = 50%

The percentage of customers who use coupons 30% and 35% pay with debit card.

Now calculate the probability that the same person will use coupon:

P[Uses coupons | Pays with Debit card] = P[Uses coupons and pays with debit card] / P[ Pays with debit card]

= 0.3 * 0.5 / 0.35

= 3/7 or 0.4286 or 42.86%