Question

A boat goes 10 km downstream and comes back to the starting point in 2 hours. If the speed of the current is 3 km/hr, then the speed of the
boat in still water is:
07 km/hr
9 km/h
10 km/hr
O 5 km/hr​

Answer 1

Step-by-step explanation:

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ur answer is

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Answer 2

The boat's speed in the still water is 9 Km/hr.

Given,

A boat goes 10 km downstream and returns to the starting point in 2 hours.

The speed of the current is 3 km/hr.

To Find,

The speed of the boat in still water.

Solution,

Let's solve the question,

Speed of boat in still water = x Km/hr

Speed of current = 3 Km/hr.

DownStream = x+3.

UpStream = x -3.

Time taken = 3hrs.

⇒ $\frac{10}{x+3} + \frac{10}{x-3} = 2$

⇒$10(\frac{x-3+x+3}{x^{2} -9}) = 2$

⇒$\frac{10*2x}{x^{2} -9} =\frac{2}{1}$

⇒ 20x=2x²-18

the equation formed is

x² - 10x - 9 = 0

x²- 9x - 1x -9 = 0

x(x - 9) + 1 (x - 9)

x = 9.

The boat's speed in the still water is 9 Km/hr.

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