Question

A car went 345 miles in 6 hours, traveling part of the time at 55 miles per hour and part of the time at 65 miles per hour. How long did the car travel at each speed?

The car travels hours at 55 miles per hour.
(Type an integer or a decimal.)

Answer 1

247.5 miles/4.5 hours at 55 mph

97.5 miles/1.5 hours at 65 mph

Explanation:

Set this up as a system of equations:

x is hours at 55 mph

y is hours at 65 mph

y = 6 - x (because there are 6 hours in total and x + y = 6)

55x + 65y = 345

55x + 65(6 - x) = 345

55x + 390 - 65x = 345

-10x = -45

x = 4.5 hours

At 55 mph the car travelled 247.5 miles in 4.5 hours.

At 65 mph the car travelled 97.5 miles in 1.5 hours.