Question

A round trip takes 3.5 hours going one way and 2 hours to return, if the trip back is at a speed 15 mph faster than the speed of the first trip. Find the speeds each way and the distance between the places.

Answer 1

first trip 20 mph, trip back 35 mph, distance = 70 miles.

Explanation:

A round trip takes 3.5 hours going one way and 2 hour to return.

Let the speed of first trip = v mph

Given that the trip back is at a speed 15 mph faster than the speed of first trip.

Therefore, the speed of trip back = ( v+15 ) mph

Let the Distance between places = d miles

Now we use the formula

`Time=(Distance)/(Velocity)`

`(Distance)/(Velocity)` = 3.5

and
`(D)/(V+15)` = 2

dividing these two

`(v+15)/(v)` =
`(3.5)/(2)`

2v + 30 = 3.5v

v = 20 mph

d = 3.5 × 20 = 70 miles

The speed of the first trip is 20 mph and the speed of trip back (20+15) 35 mph. and the distance is 70 miles.