SOLUTION: Annette drives her car 140 miles and has an average of a certain speed. If the average speed had been 3mph more, she could have traveled 147 miles in the same length of time. What

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Question 1157562: Annette drives her car 140 miles and has an average of a certain speed. If the average speed had been 3mph more, she could have traveled 147 miles in the same length of time. What was her average speed?

Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
.

The condition gives you THIS "time" equation

    140%2Fx = 147%2F%28x%2B3%29.


where "x" is the unknown speed value under the problem's question.


Cross multiply and solve

    140*(x+3) = 147x

    140x + 140*3 = 147x

    140*3 = 147x - 140x

    140*3 = 7x

    x = %28140%2A3%29%2F7 = 20*3 = 60 mph.    ANSWER

Solved.