Justin rode his bike four miles in 20 minutes (Read Description)

Question

Justin rode his bike four miles in 20 minutes. His mother drove her car the same distance in two-fifths that time. In miles per hour, what was his mother's average speed?

Answer 1

Hello! You will need to convert miles per minute to miles per hour. Justin road his bike four miles in 20 minutes. In one hour there a total of 60 minutes, so you divide: 60/20= 3. That means that in one hour, Justin will travel three times more. So you multiply: 4*3= 12. This means in one hour, Justin is traveling a total distance of 12 miles, which also means he is traveling 12 miles per hour. 

 

Justin's Mom is driving her car at X Average speed but travels the same distance as Justin except in 2/5 of time. This implies that Mom is going faster than Justin, hence a higher velocity in terms of miles per hour. 

2/5= 0.4 

 

x=12/0.4

x= 30 

 

Justin's Mom was traveling at 30 miles per hour.