Your friend lives 16 miles away. If it is 6:24, how fast would you need to drive to arrive at your friend's house by 6:45?

Question

Need to explain the reasoning of the answer. 

Answer 1

Time required to get there = 6:45 - 6:24 = 21 minutes

speed = 16 miles/21 minutes = 0.7619 miles/minute

To convert this to miles per hour (a much more useable unit)...

0.7610 miles/minute x 60 minutes/hour = 45.7 miles per hour

So, you should travel at 46 mph to get there on time.