Question

A student walks and jogs to college each day. The student averages 5 mph walking and9mph jogging. The distance is 8. She makes the trip in one hour. How far does the student jog?

Answer 1

Let x = the distance jogged

Then (8-x) = distance walked

:

Write a time equation: Time = dist/speed

:

Jog time + walk time = 1 hr

x%2F9 + %28%288-x%29%29%2F5%29 = 1

:

Multiply thru by 45 to get rid of the denominators, resulting in:

5x + 9(8-x) = 45

:

5x + 72 - 9x = 45

-4x = 45 - 72

-4x = -27

x = -27/-4

x = + 6.75 km jogged

:

:

Check: 8 - 6.75 = 1.25 km walked

6.75/9 + 1.25/5 =

.75 + .25 = 1