i am confused

jennifern83

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Nov 15, 2009
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a car traveling 63 miles per hour passes a bus traveling 56 miles in the same direction on the highway. if they maintain their speeds how long will it take them to be 14 miles apart
 
They are headed in the same direction, and we know d=rt.

\(\displaystyle \text{distance traveled by car}=63t\)

\(\displaystyle \text{distance traveled by bus}=56t\)

This difference must be 14.

\(\displaystyle 63t-56t=14\)

Solve for t.
 
Hello, jennifern83!

There is a back-door approach to this problem.
(You can do it "in your head".)


A car traveling 63 miles per hour passes a bus traveling 56 miles in the same direction.
if they maintain their speeds, how long will it take them to be 14 miles apart?

\(\displaystyle \text{The car is moving }\,63 - 56 \:=\: 7\text{ mph faster than the bus.}\)

\(\displaystyle \text{It is }as\: i\:\!\!f\text{ the bus is stopped and the car is moving by at 7 mph.}\)

\(\displaystyle \text{Therefore, the car will be 14 miles ahead in two hours.}\)

 
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