Question

A boat can move downstream at a speed of 16 km/h and upstream at a speed of 9 km/h. what is the speed of the stream and the speed of the boat in still water?​

Answer 1

let the speed of boat in still water be X km/hr and the speed of stream be Y km/hr

Speed downstream =(X+Y)km/hr

Speed upstream. = (X-Y)km/hr

x+y = 16. ......(i)

x-y. = 9. .....(ii)

Adding (i) and (ii)

x+y + x-y. = 16+9

2x = 25/2

x =12.5

therefore, y =3.5

so, speed of boat in still water is 12.5km/hr

speed of stream in still water is 3.5km/hr