Question

The speed of the flow of a river is 3 km/h * r . A motorboat goes 12km downstream and comes back in a total time of 3 hours. Find the speed of the motorboat in still water. (the speed of flow of water is less than the speed of the boat)​

Answer 1

Step-by-step explanation:

Letspeedofstream=xkm/hr

then(

9+x

15

)+(

9−x

15

)=3+(

4

3

)hour

15(

81−x

2

9−x+9+x

)=(

4

15

)

72=81−x

2

∴x

2

=81−72

∴x=3km/hr