when did her engine trouble start

Question

A race car driver averaged

140

miles per hour over the first part of the​ race, but engine trouble dropped her average speed to

100

miles per hour for the rest of the race. If the

380​-mile

race took the driver

3

hours to​ complete, after what period did her engine trouble​ start?

Answer 1

140 (3-t) + 100 t = 380

420 - 140t + 100 t = 380

-40t = -40

t=1

SHe went 280 miles before the engine problems began and 100 miles afterward.

The engine problems began 2 hours into the race