Question

Alysha’s average speed when walking home from the market was 5 mph, and it takes her 21 minutes longer than when she drives to the market. If she drives along the same route, at an average speed that is 8 times her average walking speed, how many minutes does it take her to drive home from the market?

Answer 1

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Answer:

3 minutes

Explanation:

Let x represent Alysha's time to drive home from the market.

Speed and time are inversely proportional to each other (for the same distance), so we have ...

(walking speed)(walking time) = (driving speed)(driving time)

5(x +21) = (8·5)(x)

x +21 = 8x . . . . . . . . . divide by 5

21 = 7x . . . . . . . . subtract x

3 = x . . . . . . .divide by 7

It takes Alysha 3 minutes to drive home from the market.