SOLUTION: On a trip, Marigo drove 75 miles per hour for 3 hours and then drove 40 miles per hour for 4 hours. What is Marigo's average rate of speed in miles per hour for the enitre trip?

Algebra ->  Expressions-with-variables -> SOLUTION: On a trip, Marigo drove 75 miles per hour for 3 hours and then drove 40 miles per hour for 4 hours. What is Marigo's average rate of speed in miles per hour for the enitre trip?       Log On


   

Question 157827: On a trip, Marigo drove 75 miles per hour for 3 hours and then drove 40 miles per hour for 4 hours. What is Marigo's average rate of speed in miles per hour for the enitre trip?
PLEASE HELP!
Answer by gonzo(654) About Me  (Show Source):
You can put this solution on YOUR website!
rate * times = distance
75 miles per hour * 3 hours = 225 miles.
40 miles per hour * 4 hours = 160 miles.
total trip was 225 + 160 miles = 385 miles.
total time was 7 hours.
average speed for the whole trip was 385 miles / 7 hours = 55 miles per hour.