SOLUTION: A riverboat can travel downstream from port A to port B at 20 mph. It can travel upstream from port B to port A at 15 mph. If it takes 5 hours to go upstream than downstream, what

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Question 848267: A riverboat can travel downstream from port A to port B at 20 mph. It can travel upstream from port B to port A at 15 mph. If it takes 5 hours to go upstream than downstream, what is the distance between ports A and B?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = the time in hours to go downstream
+t+%2B+5+ = the time to go upstream
Let +d+ = the distance in miles from A to B
------------------
Equation for going downstream:
(1) +d+=+20t+
Equation for going upstream:
(2) +d+=+15%2A%28+t+%2B+5+%29+
----------------------
Substitute (1) into (2)
(2) +20t+=+15t+%2B+75+
(2) +5t+=+75+
(2) +t+=+15+
and
(1) +d+=+20t+
(1) +d+=+20%2A15+
(1) +d+=+300+
the distance between A an B is 300 mi
check:
(2) +d+=+20t+
(2) +300+=+20t+
(2) +t+=+15+
OK