Question

On a 5 hour trip, Thomas drove part of the time at 30 mi/h and the rest at 55 mi/h. If he traveled a distance of 250 mi, how much time did he spend driving at 55 mi/h?

Answer 1

Answer:he spent 1 hour driving at 55 mikes per hour

Explanation:

Let x represent the time that Thomas spent driving at 30 miles per hour.

Let y represent the time that Thomas spent driving at 55 miles per hour.

Total time for the trip is 5 hours. This means that

x + y = 5

Distance = speed × time

Distance travelled at 30 miles per hour for x hours = 30×x = 30x miles

Distance travelled at 55 miles per hour for y hours = 55×y = 55y miles

If he traveled a distance of 250 miles, therefore

30x + 55y = 250 - - - - - - -1

Substituting x = 5 - y into equation 1, it becomes

30(5 - y) + 55y = 250

150 - 30y + 55y = 250

- 30y + 55y = 250 - 150

25y = 100

y = 100/25

y = 4

y = 5 - x = 5 - 4

y = 1