A man can row 15 km per hour downstream and 9 km per hour upstream. The speed (in kmph) of the boat in still water is

• 10

• 12

• 15

• 15

A boat covers 12 km upstream and 18 km downstream in 3 hours, while it covers 36 km upstream and 24 km downstream in 

What is the speed of the current?

• 1.5 km/hr

• 1 km/hr

• 2 km/hr

• 2.5 km/hr

A man can row against the current three-fourth of a kilometre in 15 minutes and returns the same distance in 10 minutes. The ratio of his speed to that of the current is

• 3 : 5

• 5 : 3

• 1 : 5

• 1 : 5

A boat moves downstream at the rate of 1 km in  minutes and upstream at the rate of 5 km an hour. what is the speed of the boat in the still water?

• 
• 

• 4 km/hour

• 4 km/hour

If the speed of a boat in still water is 20 km/hr and the speed of the current is 5 km/hr, then the time taken by the boat to travel 100 km with the current is

• 2 hours

• 3 hours

• 4 hours

• 4 hours

A boat moves downstream at the rate of 8 km/hr and upstream at 4 km/hr. The speed of the boat in still water is:

• 4.5 km/hr

• 5 km/hr

• 6 km/hr

• 6.4 km/hr

Speed of a boat along and against the current are 14 km/hr and 8 km/hr respectively. The speed of the current is

• 11 km/hr

• 6 km/hr

• 5.5 km/hr

• 3 km/hr

A man can row 6 km/h in still water. If the speed of the current is 2 km/h, it takes 3 h more in upstream than in the downstream for the same distance. The distance is

• 30 km

• 24 km

• 20 km

• 32 km

9.

A ship is moving at a speed of 30 km/h. To know the depth of the ocean beneath it. It sends a radio wave which travels at a speed 200 m/s. The ship receives the signal after it has moved 500 m. The depth of the ocean is

• √143/2 km

• 12 km

• 6 km

• 8 km

A swimmer swims from a point A against a current for 5 min and then swims backwards in favour of the current for next 5 min and comes to the point B. If AB = 100 m, then the speed of the current in (km/h) is

• 1

• 0.6

• 0.4

• 0.2