<PRE><B>Question 312898</B>
let speed of boat in still water be x mph
..
downstrea+ the speed will be x+5 mph
distance traveled = 45 miles.
time taken = 45/ x+5
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up stream the speed will be x-5 mph
distance traveled = 25 miles
time taken = 25/ x-5
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both take same time
..
45/x+5 = 25/x-5
45(x-5)=25(x+5)
45x-225=25x+125
45x-25x=350
20x=350
x= 17.5 mph speed of boat in still air
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