I drove to the beach at a rate of 40 miles per hour. If I had driven at a rate of 30 miles per hour instead, then I would have arrived 20 minutes later. How many miles did I drive?
Distance is the same regardless of the speed for this question
rate x time = distance
40 m/h * x = distance
30 m/h * (x + 1/3) = distance 1/3 = 1/3 hour = 20 minutes
40x = 30 (x+1/3)
40x = 30x + 10
10x = 10
x = 1 hr
40 m/hr x 1 hr = 40 miles check 30 m/h x 1 1/3 = 40 miles Check!