A paddle boat can move at a speed of 6 km/h in still water. The boat is paddled 16 km downstream in a river in the same time it takes to go 8 km upstream. What is the speed of the river?
Answer (2)
v − t h e s p ee d o f t h e r i v er 16 : ( 6 + v ) = 8 : ( 6 − v ) 6 + v 16 = 6 − v 8 − − − − − − − − − − − − − m u lt i pl y o n t h e cross − − − − − − − − − − − − − 8 ( 6 + v ) = 16 ( 6 − v ) 48 + 8 v = 96 − 16 v 8 v + 16 v = 96 − 48 24 v = 48 / : 24 v = 2 ( km / h ) ← A n s w er
The speed of the river is determined to be 2 km/h. This is found by setting up an equation based on the time taken to travel downstream and upstream. By solving the equation, we find the river's speed.
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