Question

the speed of boat in still water is 15km/hour. it can go 30km upstream and return downstream to the orginal point in 4 hour 30 min. find the speed of the boat.

Answer 1

Answer:

Step-by-step explanation:

Let the speed of the stream = x km/h

Speed of boat in, upstream = (x-15) km/h

                             downstream = (x+15) km/h

Time taken to go, upstream = 30/(x-15) h

                              downstream = 30/(x+15) h

A.T.P.

30/(x-15) + 30/(x+15) = 4+1/2

[30(x+15) + 30(x-15)]/(x-15)(x+15) = 9/2

2*[30x+30x+450-450] = 9(x^2 -225)

120x = 9x^2 - 2025

3x^2 - 40x - 675 = 0

Answer 2

Step-by-step explanation:

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