# Algebra

The time, t, required to drive a certain distance varies inversely with the speed, r. If it takes 7 hours to drive the distance at 55 miles per hour, how long will it take to drive the same distance at 65 miles per hour?

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1. since ts = k is constant,
and 65 = 13/11 * 55,

(7)(55) = (11/13 * 7)(13/11 * 55)
11/13 * 7 = 5.92

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2. It always help to see how it is done. Thanks.

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3. you can also see that since st is constant,

65t = 55*7

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