SOLUTION: The speed of a stream is 6 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream, what is the speed of the boat in still water?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: The speed of a stream is 6 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream, what is the speed of the boat in still water?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 142033: The speed of a stream is 6 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream, what is the speed of the boat in still water?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
he speed of a stream is 6 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream, what is the speed of the boat in still water?
:
Let s = speed in still water
then
(s-6) = speed upstream (in relation to the land)
and
(s+6) = speed downstream
:
Write a time equation: Time = dist/speed
:
Time downstream = time upstream
98%2F%28s%2B6%29 = 49%2F%28s-6%29
Cross multiply
98(s-6) = 49(s+6)
:
98s - 588 = 49s + 294
:
98s - 49s = 294 + 588
:
49s = 882
s = 882%2F49
s = 18 mph in still water
:
:
Check solution by finding out if the times are equal
12 mph = speed up
24 mph = speed down
49/12 = 4.0833
98/24 = 4.0833