A farmer drives a tractor from one town to another, a distance of 120 kilometers. He drives 10 kilometers per hour fast on the return trip, cutting an hour off the time. How fast does he drive each way?

Question

Chanel Olsen

Mathematics

24 May, 22:14

A farmer drives a tractor from one town to another, a distance of 120 kilometers. He drives 10 kilometers per hour fast on the return trip, cutting an hour off the time. How fast does he drive each way?

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Answers (1)

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Freddie · Answer 1

120/x - 120 / (x+10) = 1

120x + 1200 - 120x = x (x+10)

1200 = x^2+10x

x^2 + 10x - 1200 = 0

(x+40) (x-30) = 0

Positive solution:

x = 30 km/hr (rate on the 1st trip)

x+10 = 40 km/hr (rate on the return trip)