Julian rides his bike uphill for 45 minutes, then turns around and rides back downhill. It takes him 15 minutes to get back to where he started. His uphill speed is 3 miles per hour slower than his downhill speed. Find Julian's uphill and downhill speed.

Question

Physics

First Mate

1 July, 01:46

Julian rides his bike uphill for 45 minutes, then turns around and rides back downhill. It takes him 15 minutes to get back to where he started. His uphill speed is 3 miles per hour slower than his downhill speed. Find Julian's uphill and downhill speed.

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Answers (1)

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Braeden Kirby · Answer 1

1.5mi/hr, 4.5mi/hr

Explanation:

Given:

45 min = 0.75h, 15 min = 0.25h

(1) 0.75v₁ = 0.25v₂

(2) v₁ = v₂ - 3

Solve for v₁ and v₂:

0.75 (v₂ - 3) = 0.25v₂ = 0.75v₂ - 2.25 = 0.25v₂

0.5v₂ = 2.25

v₂ = 4.5

v₁ = 1.5