Question

Doug’s average driving speed is 1 kilometers per hour faster than Thor’s. In the same length of time it takes Doug to drive 390 kilometers, Thor drives only 384 kilometers. What is Doug’s average speed?

Answer 1

Doug speed will be 65 km/hr

Step-by-step explanation:

Let the Thor's speed is x km/hr

So Doug's speed = x+1 km/hr

We have given that Doug and Thor take same time to cover 390 km and 384 km respectively

We know that time is given by

`time=(distance)/(speed)`

So time taken by Doug to cover the distance

`time=(390)/(x+1)`

And time taken by Thor to cover the distance

`time=(384)/(x)`

As both times are equal

So
`(390)/(x+1)=(384)/(x)`

`6x=384`

`x=64km/hr`

So Doug speed will be 64+1 = 65 km/hr