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

Mathematics

Josiah Matthews

19 July, 03:50

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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Cade Sims · 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)