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sergiy2304 [10]

2 years ago

9

A boat travels 105 km downstream in 5 hours. The return trip upstream takes 7 hours. Find the speed of the boat in still water a

nd the speed of the current.

1 answer:

notsponge [240]2 years ago

4 0

Speed of the boat = u
speed of the current = v

in downstream,
u - v = 105/5
u - v = 21

in upstream
u + v = 105/7
u + v = 15

add both equations
2u = 36
u = 18

v = -3

so
speed of the boat = 18 km/h
speed of the current = 3 km/h

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