If a person goes 20 kilometre downstream in 5 hours and returns against the stream in 15 hours, then the speed of the stream in kilometre per hour is :

Pipes A and B can fill a tank in 20 hours and 30 hours respectively and pipe C can empty the full tank in 40 hours. If all the pipes are opened together, how much time will be needed to make the tank full ?

In a game of carrom of 100 points, A can give B 20 points and C 40 points, then points B can give C is:

A man rows 8 km upstream in 4 hours and 16 km downstream in 4 hours . What is the speed of the current?

A shopkeeper has 10 litres of pure honey. He sells honey at the cost price of Rs. 300 per litre. After mixing some quantity of water in pure honey he sells the syrup of pure honey and water at Rs. 250 per litre. The quantity of water mixed in pure honey is

A container contains 50 litres of milk. From this container 10 litres of milk was taken out and replaced by water. This process is repeated two more times. How much milk is now left in the container ?

The cost of type A cement is Rs 100 per kg and that of type B cement is Rs 120 per kg. If both are mixed in the ratio of 2:3, the price of the cement mixer per kg will be