A student flips a coin four times. What is the probability the coin lands tails up exactly three times?

Question

A student flips a coin four times. What is the probability the coin lands tails up exactly three times?

Answer 1

First, think about number of ways that we can get 3 tails. You can show that there are exactly four ways.

Next, how many total outcomes are there for flipping coin four times? Each toss has two possible outcomes. So, total number is 2*2*2*2 = 16.

So, probability is 4/16 = 25%.