Q. 304.7( 6 Votes )

A motorboat whose

Answer :

Let the speed of the stream be x km/h.

The speed of the boat upstream = (18 – x) km/h

And the speed of the boat downstream = (18 + x) km/h

We know that time = distance/speed

Time taken to go upstream hours

Also, time taken to go downstream hours


24 (18 + x) – 24 (18 – x) = (18 – x) (18 + x)

x2 + 48x – 324 = 0

We know that quadratic formula

Using the quadratic formula, we get

= 6 or -54

Since x is the speed of the stream, it cannot be negative.

x = 6 gives the speed of the stream as 6 km/h.

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