Question

The speed of a boat in still water is 15 km/hr. It can go 30 km upstream

and return downstream to the

original point in 7 hours 12 minutes. Find the speed of the stream.

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Answer 1

Answer:

10 km/h

Step-by-step explanation:

speed of boat in still water = 15km/h

total distance%= 30km

total time = 7h 12 min= 7+12/60=7+1/5=36/5 h

let speed of stream= x km/h

speed of boat in up= (15-x) km/h

taken time = D/S= 30/(15-x) h

speed of boad down stream= (15+x) km/h

the streamtaken time= 30/(15+x) h

total time

30/(15-x) + 30/(15+x) = 36/5

30×30/(225-x²)= 36/5

25×5 = 225-x²

125-225= -x²

-100 = -x²

x²= 100

x=10 km/h = speed of