SOLUTION: Ben's average driving speed for a 5 hour trip was 35 miles per hour. During the first four hours, he drove 30 miles per hour. What was his average speed for the last hour of his tr

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Ben's average driving speed for a 5 hour trip was 35 miles per hour. During the first four hours, he drove 30 miles per hour. What was his average speed for the last hour of his tr      Log On


   

Question 274978: Ben's average driving speed for a 5 hour trip was 35 miles per hour. During the first four hours, he drove 30 miles per hour. What was his average speed for the last hour of his trip?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Ben's average driving speed for a 5 hour trip was 35 miles per hour.
During the first four hours, he drove 30 miles per hour.
What was his average speed for the last hour of his trip?
:
Let s = his speed the last hr of he trip
:
Write a distance equation: dist = speed * time
;
35 mph dist + unknown speed dist = total dist
30(4) + 1s = 35(5)
120 + s = 175
s = 175 - 120
s = 55 mph for the last hr
;
:
Check this
120 + 55 = 175