SOLUTION: Rachel paddles her canoe upstream on the Econ River for 45 minutes. Coming downstream with the same boat speedtook 30 minutes. If the current river speed is 3 mph, what was her b

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Question 411179: Rachel paddles her canoe upstream on the Econ River for 45 minutes. Coming downstream with the same boat speedtook 30 minutes. If the current river speed is 3 mph, what was her boat speed.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The distance is the same going both ways
upstream:
d+=+%28s+-+3%29%2A%283%2F4%29
d+=+%283%2F4%29%2As+-+9%2F4
---------------
downstream:
d+=+%28s+%2B+3%29%2A%281%2F2%29
d+=+%281%2F2%29%2As+%2B+3%2F2
---------------
%283%2F4%29%2As+-+9%2F4+=+%281%2F2%29%2As+%2B+3%2F2
%281%2F4%29%2As+=+9%2F4+%2B+6%2F4
%281%2F4%29%2As+=+15%2F4
s+=+15
Her boat speed was 15 mi/hr
check answer:
d+=+%2815+-+3%29%2A%283%2F4%29
d+=+9 mi
d+=+%28s+%2B+3%29%2A%281%2F2%29
d+=+%2815+%2B+3%29%2A%281%2F2%29
d+=+9 mi
OK