Average rate

Question

A truck can travel 175 miles in the same time that it takes a car to travel 225 miles. If the trucks rate is 10 miles per hour slower than the cars, find the average rate for each.

Answer 1

distance=rate*time

d=r*t

r=car's rate

r-10=truck's rate

175=(r-10)*t

225=r*t

225/r=t

substitute

175=(r-10)*(225/r)

multiply both sides by r

175r=(r-10)(225)

175r=225r-2250

175r-225r=-2250

-50r=-2250

50r=2250

r=2250/50

r=45 mph for the car's rate

r-10=45-10=35 mph for the truck's rate