SOLUTION: Andy's average driving speed for a 4-hour trip was 45 miles per hour. During the first 3 hours he drove 40 miles per hour. what was his average speed for the last hour of his trip?

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Question 606971: Andy's average driving speed for a 4-hour trip was 45 miles per hour. During the first 3 hours he drove 40 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!
Andy's average driving speed for a 4-hour trip was 45 miles per hour.
During the first 3 hours he drove 40 miles per hour.
what was his average speed for the last hour of his trip?
:
let s = speed on the last hr
;
Write a distance equation; dist = speed * time
40(3) + 1s = 45(4)
120 + s = 180
s = 180-120
s = 60 mph on the last hr