Question

The speed of a boat downstream is 12 kmph and its upstream is 6kmph.Find the speed of the boat in still water and the speed of the stream ​

Answer 1

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Given ,

The speed of the boat downstream = 12 km/hr

The speed of the boat upstream = 6 km/hr

Let , the speed of boat in still water be x

and the speed of stream be y

So ,

The speed of the boat downstream is (x + y) i.e

x + y = 12 ------ (i) {given}

The speed of the boat upstream is (x - y) i.e

x - y = 6 ------ (ii) {given}

Add equation (i) and (ii) , we get

2x = 18

x = 9

Put the value of x = 9 in eq (i) , we get

9 + y = 12

y = 3

Hence , the speed of boat in still water and the speed of the stream are 9 km/hr and 3 km/hr