# Difference between revisions of "2019 AMC 8 Problems/Problem 16"

## Problem 16

Qiang drives $15$ miles at an average speed of $30$ miles per hour. How many additional miles will he have to drive at $55$ miles per hour to average $50$ miles per hour for the entire trip?

$\textbf{(A) }45\qquad\textbf{(B) }62\qquad\textbf{(C) }90\qquad\textbf{(D) }110\qquad\textbf{(E) }135$

The only option that is easily divisible by $55$ is $110$. Which gives 2 hours of travel. And by the formula $\frac{15}{30} + \frac{110}{50} = \frac{5}{2}$

And $Average Speed$ = $\frac{Total Distance}{Total Time}$

Thus $\frac{125}{50} = \frac{5}{2}$

Both are equal and thus our answer $\boxed{\textbf{(D)}\ 110}$

~phoenixfire