Question 272860
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