# Math Help - An Average Velocity Problem

1. ## An Average Velocity Problem

A driver sets out on a journey. For the first half of the distance she drives at the leisurely pace of 30 mph; she drives the second half at 60 mph. What is her average speed for the trip. Solve the problem algebraically using the formula D=r*t.

2. ## Re: An Average Velocity Problem

Originally Posted by joojoa94
A driver sets out on a journey. For the first half of the distance she drives at the leisurely pace of 30 mph; she drives the second half at 60 mph. What is her average speed for the trip. Solve the problem algebraically using the formula D=r*t.
first half ...

$t_1 = \frac{d/2}{30} = \frac{d}{60}$

second half ...

$t_2 = \frac{d/2}{60} = \frac{d}{120}$

$v_{avg} = \frac{d}{t_1+t_2}$

finish it ...