Question

42. A boat can be rowed 9 km. upstream or
18 km. downstream in a period of 3 hrs. What is the
speed of the boat in still water in km/hr?​

Answer 1

Answer:

8km/hr is the answer for this I hope

Answer 2

The speed of boat in still water = 9/2 Km/hr

Time taken by boat to row 9 Km upstream = 3 hours

Velocity of the boat upstream = 9/3

= 3 Km/hr

Time taken by boat to row 18 Km upstream = 3 hours

Velocity of the boat upstream = 18/3

= 6 Km/hr

Let the velocity of boat in still water be v and the velocity flow of river be u.

Velocity of boat upstream = velocity in still water - velocity of water

=> 3 = v - u -----(1)

Velocity of boat downstream = velocity in still water + velocity of water

=> 6 = v + u -----(2)

Solving the equations (1) and (2) we get v = 9/2 Km/hr and u = 3/2 Km/hr.

Speed of boat in still water = 9/2 Km/hr