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?
:
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