SOLUTION: A car travels 400 miles in 7 hours. Before noon the driver averages 60 miles per hour, but after noon he averages only 50 miles per hour. At what time did he leave?

Question 735653: A car travels 400 miles in 7 hours. Before noon the driver averages 60 miles per hour, but after noon he averages only 50 miles per hour. At what time did he leave?
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
A car travels 400 miles in 7 hours. Before noon the driver averages 60 miles per hour, but after noon he averages only 50 miles per hour. At what time did he leave?
***
let x=distance traveled before noon
400-x=distance traveled after noon
Travel time=distance/speed
..
travel time before noon plus travel time after noon=7 hrs

50x+24000-60x=7*50*60
-10x+24000=21000
10x=3000
x=300
travel time before noon=x/60=300/60=5 hrs
At what time did he leave? 5 hrs before noon=7 am
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