Question 203027
85x+95x=315
180x=315
x=315/180
x=1.75 hours after they leave they will be 315 km apart.
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4x+4(x+20)=400
4x+4x+80=400
8x=400-80
4x=320
x=320/8
x=40 mph for the slower car.
40+20=60 mph for the faster car.
Proof:
4*40+4*60=400
160+240=400
400=400