SOLUTION: After lunch, a tourist finds out that he has four hours at his disposal before dinner. He decides to walk along the road and return by Kalesa. The Kalesa travels at 15 kph, and he

Algebra ->  Customizable Word Problem Solvers  -> Numbers -> SOLUTION: After lunch, a tourist finds out that he has four hours at his disposal before dinner. He decides to walk along the road and return by Kalesa. The Kalesa travels at 15 kph, and he       Log On

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Question 825929: After lunch, a tourist finds out that he has four hours at his disposal before dinner. He decides to walk along the road and return by Kalesa. The Kalesa travels at 15 kph, and he walks 3 kph. Assuming that the kalesa comes on time for dinner, how far from the rest house has he walk?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = time in hours spent walking
Let +d+ = the distance that he walks in km
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Equation for walking:
(1) +d+=+3t+
Equation for Kalesa:
(2) +d+=+15%2A%28+4+-+t+%29+
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By substitution:
(2) +3t+=+15%2A%28+4-t+%29+
(2) +3t+=+60+-+15t+
(2) +18t+=+60+
(2) +t+=+3.333+
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(1) +d+=+3%2A3.333+
(1) +d+=+10+ km
He walked 10 km
check:
(2) +d+=+15%2A%28+4+-+t+%29+
(2) +d+=+15%2A%28+4+-+3.333+%29+
(2) +d+=+15%2A.667+
(2) +d+=+10+ km
OK