Time + Distance problem

Question

Two cars leave from Albany, New York, at the same time and travel directly north. One car travels one and one-half times as fast as the other. After 4 hours and 45 minutes, they are 95 miles apart. What is the speed of each car?

 

How ow do you show it on the table and work?

Answer 1

distance=rate*time

d=r*(4.75)   (slower car)

d+95=(1.5r)*(4.75)  (faster car)

replace d by 4.75r in the second equation

4.75r+95=(1.5r)(4.75)

4.75r+95=7.125r

95=7.125r-4.75r

95=2.375r

you can leave 2.375 as a decimal or change it to a mixed number

95=2 3/8*r

95=(19/8)*r

multiply both sides by 8/19

(8/19)(95)=(8/19)(19/8)(r)

40=r

r= 40 mph for the rate of the slower car

1.5r=1.5*40=60 mph for the rate of the faster car

note that 95/2.375=40 also if you prefer decimals over fractions