Question

Hong is participating in a 6-day cross-country biking challenge. He biked for 71, 59, 68, 70, and 68 miles on the first five days. How many miles does he need to bike on the last day so that his average (mean) is 64 miles per day?

Answer 1

Based on the given information, we can express the following

`64=(71+59+68+70+68+x)/(6)`

We formed that equation from the mean formula. Now, we solve for x,

`\begin{gathered} 64\cdot6=336+x \\ x=384-336 \\ x=48 \end{gathered}`

Hence, he needs to bike 48 miles on the last day to have an average of 64 miles per day.