SOLUTION: Kareem took 5hours to drive 470km from Sudbury to Brantford. For part of the trip, he drove at 100km/h. For the rest of the trip he drove at 90km/h. How far did he drive at each sp

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Kareem took 5hours to drive 470km from Sudbury to Brantford. For part of the trip, he drove at 100km/h. For the rest of the trip he drove at 90km/h. How far did he drive at each sp      Log On

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Question 272860: Kareem took 5hours to drive 470km from Sudbury to Brantford. For part of the trip, he drove at 100km/h. For the rest of the trip he drove at 90km/h. How far did he drive at each speed?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT D=distance, R=rate & T=time.
470=100X+90(5-X)
470=100X+450-90X
100X-90X=470-450
10X=20
X=20/10
X=2 HOURS DRIVING @ 100 KM/H.
5-2=3 HOURS DRIVING @ 90 KM/H.
PROOF:
470=100*2+90*3
470=200+270
470=470