Question

A radio station runs a promotion at an auto show with a money box with 10 ​$50 ​tickets, 10 ​$25 ​tickets, and 12 ​$5 tickets. The box contains an additional 20 ​"dummy" tickets with no value. Three tickets are randomly drawn. Find the probability that all three tickets have no value.

Answer 1

P = 57/1105

P = 0.052

Explanation:

Given:

Total number of dummy tickets = 20

Total number of tickets with value = 10 + 10 + 12 = 32

Total number of tickets in the box = 20 + 32 = 52

The probability of picking 3 tickets randomly from the box without replacement and the three are dummy (with no value) is;

P = 20/52 × 19/51 × 18/50

(As each one is picked it reduces the total number of tickets and also the number of dummy tickets by one)

P = 57/1105

P = 0.052