Question

A bowl contains 7 pennies, 9 nickels, and 4 dimes. Elyse removes one coin at random from the bowl and does not replace it. She then removes a second coin at random. What is the probability that both will be dimes?

Answer 1

The probability is 3/95

Explanation:

Okay this is a probability without replacement question.

Firstly we calculate the total number of coins = 7 + 9 + 4 = 20 coins

The probability that the first coin will be a dimes = number of dimes/total number of coins = 4/20 = 1/5

Now she removes a coin without replacement, if it was a dime, total number of coins becomes 19 and the total number of dimes becomes 3; Thus the probability of the second coins being a dimes = 3/19

Thus, the probability of both coins being dimes = probability of first coin being dimes * probability of second coins being dimes

= 1/5 * 3/19 = 3/95