SOLUTION: Kareem swam 5km against the current in the same amount of time that it took him to swim 15km with the current. The rate of the current was 2km per hour. how fast would Kareem swim

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Question 1047602: Kareem swam 5km against the current in the same amount of time that it took him to swim 15km with the current. The rate of the current was 2km per hour. how fast would Kareem swim if there was no current?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = Kareem's speed in the water
with no current in km/hr
Let +t+ = his time in hrs to swim
both against and with the current
------------------------------------
Kareem's speed going against the current
(1) +5+=+%28+s+-+2+%29%2At+
Kareem's speed going with the current
(2) +15+=+%28+s+%2B+2+%29%2At+
-------------------------
(1) +t+=+5%2F%28+s+-+2+%29+
and
(2) +15+%2F+%28+s+%2B+2+%29+=+t+
by substitution:
(2) +15%2F%28+s+%2B+2+%29+=+5%2F%28+s+-+2+%29+
(2) +15%2A%28+s+-+2+%29+=+5%2A%28+s+%2B+2+%29+
(2) +15s+-+30+=+5s+%2B+10+
(2) +10s+=+40+
(2) +s+=+4+
-------------------
Kareem can swim 4 km/hr with no current
-------------------
check:
(1) +5+=+%28+4+-+2+%29%2At+
(1) +5+=+2t+
(1) +t+=+5%2F2+
and
(2) +15+=+%28+4+%2B+2+%29%2At+
(2) +15+=+6t+
(2) +t+=+5%2F2+
OK