From a point on a straight road Marco and Celeste ride bicyc

From a point on a straight road, Marco and Celeste ride bicycles in the same direction. Marco rides at 10 mph and Celeste rides at 12 mph. In how many hours will they be 15 mi apart?

Solution

Marco rides at 10 mph

Celeste rides at 12 mph

Let after x hrs they are 15 mi apart

distnace travelled by Marco = 10*x

distance travelled by Celecte = 12x

So, 12x - 10x = 15

2x = 5 ; x = 2.5 hrs they will be 15 mi apart