SOLUTION: car travels a total of 275 miles in 4 hours, traveling part of the time at 60 mph and part of the time at 74 miles per hour. how long did the car travel at each speed?

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Question 903271: car travels a total of 275 miles in 4 hours, traveling part of the time at 60 mph and part of the time at 74 miles per hour. how long did the car travel at each speed?
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
a+b=4,
60*a+74*b=275
a=4-b
60*(4-b)+74*b=275
240-60b+74*b=275
14*b=35
b=2.5
a=4-b
a=1.5 hours at 60 mph and b=2.5 hours at 74 mph
check
1.5+2.5=4
60*a+74*b=275
60*1.5+74*2.5=275
90.0+185.0=275
275.0=275
ok