Question

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 25 minutes later. How many miles did I drive?

Answer 1

Step-by-step explanation:

x = number of hours driven

25 minutes = 5/12 hour

remember,

1 hour = 60 Minuten

5 minutes = 60/12 minutes = 1/12 hour

25 minutes = 5×5 minutes = 5/12 hour

x hours × 40 miles/hour = (x + 5/12) hours × 30 miles/hour

the dimensions "hour" eliminate each other from the top and the bottom of the fractions leaving only miles. and the miles must be the same either way.

40x = (x + 5/12)×30 = 30x + 150/12

10x = 150/12

x = 15/12 = 5/4 hours

40 miles/hour × 5/4 hours = 40×5/4 miles = 10×5 = 50 miles.

I drove 50 miles.