SOLUTION: a boats crew rowed 9 miles down stream with a current, in 1.5hrs. the return trip upstream against current covered same distance but took 3 hours find crews row rate in still water
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Question 578652: a boats crew rowed 9 miles down stream with a current, in 1.5hrs. the return trip upstream against current covered same distance but took 3 hours find crews row rate in still water and the rate of current Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! Boat speed =x mph
current speed =y mph
against current , x-y 3 hours
with current , x+y 1.5 hours
Distance = same= 9 miles
t=d/r against current
9.00 / ( x - y )= 3.00
9.00 ( x - y ) = 3.00
3.00 x - -3.00 y = 9.00 ....................1
9.00 / ( x + y )= 1.50
1.50 ( x + y ) = 9.00
1.50 x + 1.50 y = 9.00 ...............2
Multiply (1) by 1.00
Multiply (2) by 2.00
we get
3.00 x + -3.00 y = 9.00
3.00 x + 3.00 y = 18.00
6.00 x = 27.00
/ 6.00
x = 4.5 mph
plug value of x in (1)
3 x -3 y = 9
13.5 -3 y = 9
-3 y = 9 -13.5
-3 y = -4.5
y = 1.5 mph
Boat 4.5 mph
current 1.5 mph
