# What is the average speed for the entire trip?

A train leaves on station 80 miles/hour for 3.5 hours and 70 miles/hour for 2 hours to reach it's destination. What was the average seed for the entire trip.

• Welcome to math.SE: In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level. Jul 24, 2017 at 23:16
• im sorry sir.. yes i'll do it next time but this problem i really don't know the formula thanks.. Jul 24, 2017 at 23:22
• No need to apologize! It's just always encouraged to see your work so finding the answer can be a learning experience. Jul 24, 2017 at 23:24

\begin{aligned} \text{Average speed}&=\frac{\text{total distance traveled}}{\text{total time traveled}}\\[5pt] &=\frac{80\cdot 3.5+70\cdot 2}{3.5+2}\\[5pt] &=\frac{420}{5.5}\\[5pt] &=76.\overline{36} \end{aligned}