Question 579988: A car went 372 miles in 6 hours, traveling part of the time at 55 mph and part of the time at 70 mph. How long did the car travel at each speed?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! A car went 372 miles in 6 hours, traveling part of the time at 55 mph and part of the time at 70 mph.
How long did the car travel at each speed?
:
Let t = time traveling at 70 mph
the total time was given as 6 hrs, therefore
(6-t) = time traveling at 55 mph
:
Write a distance equation, dist = speed * time
:
70mph dist + 55mph dist = 372 mi
70t + 55(6-t) = 372
70t + 330 - 55t = 372
70t - 55t = 372 - 330
15t = 42
t = 42/15
t = 2.8 hrs at 70 mph
then
6 - 2.8 = 3.2 hrs at 55 mph
;
:
Check this by finding the dist at each speed
2.8(70) = 196 mi
3.2(55) = 176 mi
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total dist :372 mi
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