Question

10. A motor boat heads upstream a distance of 24km on a river whose current is running at 3
km per hour. The trip up and back takes 6 hours. Assuming that the motor boat maintained
a constant speed, what was its speed?
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Answer 1

Answer:

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Its speed is 9km/hr.

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Step-by-step explanation:

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It is given in the below photo

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Hope my answer helps.....

Answer 2

Answer: 9km/h

Step by Step explaination:

let speed of boat be xkm/h

so upstream = (x-3) km/h

and down stream = (x+3) km/h

according to the question boat takes 6 hrs to go up and back in the current

so,

24/x+3 + 24/x-3 = 6

1/x+3 + 1/x-3 = 6/24

x-3+x+3/(x+3)(x-3) = 1/4

2x/x²-9 = 1/4

8x = x²-9

x² - 8x - 9 = 0

(x - 9)(x + 1) = 0

so, x = 9, - 1

as speed can't be negative so the value of x will be x = 9km/h