SOLUTION: John took a drive to town at an average rate of 40 mph. In the evening, he drove back at 30
mph. If he spent a total of 7 hours traveling, what is the distance traveled by John?
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-> SOLUTION: John took a drive to town at an average rate of 40 mph. In the evening, he drove back at 30
mph. If he spent a total of 7 hours traveling, what is the distance traveled by John?
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Question 1156011: John took a drive to town at an average rate of 40 mph. In the evening, he drove back at 30
mph. If he spent a total of 7 hours traveling, what is the distance traveled by John? Found 2 solutions by ikleyn, josgarithmetic:Answer by ikleyn(52803) (Show Source):
Let "d" be one-way distance.
He spent hours driving "to there".
He spent hours driving back.
The total time is 7 hours:
+ = 7 hours.
You get your basic equation. It is called the "time" equation.
To solve it, multiply both sides by 120. You will get
3d + 4d = 7*120
7d = 7*120
d = 120 kilometers.
ANSWER. One way distance is 120 kilometers. Total (two-ways) distance is 240 km.
CHECK. + = 3 + 4 = 7 hours. ! Precisely correct !
SOLVED.
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Using "time" equation is a STANDARD method of solving such problems.
From this lesson, learn on how to write, how to use and how to solve a "time" equation.