SOLUTION: A car traveled 462 km in 7 h. for the last 3 h of the trip its average speed was 20 km/h less than twice its average speed for the first 4 h. find the two speeds at which the car t
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Question 535236: A car traveled 462 km in 7 h. for the last 3 h of the trip its average speed was 20 km/h less than twice its average speed for the first 4 h. find the two speeds at which the car traveled. (using uniform motion) Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! A car traveled 462 km in 7 h. for the last 3 h of the trip its average speed was 20 km/h less than twice its average speed for the first 4 h.
find the two speeds at which the car traveled. (using uniform motion)
:
Let s = car speed the 1st 4 hrs
then
(2s-20) = speed the last 3 hrs"
:
Write a distance equation; dist = speed * time
:
4s + 3(2s-20) = 462
4s + 6s - 60 = 462
10s = 462 + 60
10s = 522
s = 522/10
s = 52.2 km/hr the 1st 4 hrs
then
2(52.2) - 20 = 84.4 km/hr the last 3 hrs
:
:
You can check these solutions, find the distance at each speed, should equal 462 km
