Question

Emily takes a trip, driving with a constant velocity of 85.5 km/h to the north except for a 22 min rest stop. If Emily's average velocity is 68.8 km/h to the north, how long does the trip take? Show your work

Answer 1

Answer:

1½ hours

Explanation:

Let the amount of time she drove at 85.5 km/hr be t, then

The distance that she rode would be 85.5 * t

This is means Emily has traveled the same distance at 68.8 km/hr without any stoppage whatsoever. Thus, we can create an equation as such

85.5 * t = 68.8 (t + 22/60), the 22/60 being, converting 22 minutes into hours. We proceed further as

85.5t = 68.8t + 1513.6/60, multiplying all sides by 60, we have

5130t = 4128t + 1513.6, now we collect like terms

5130t - 4128t = 1513.6

1002t = 1513.6

t = 1513.6/1002

t = 1.51 hrs, or in minutes, 1.51 * 60

t = 90.63 minutes. 1 hour and 36 minutes

So the total time the trip took, 22 minutes in addition, or say, 1 hour 58 minutes.