A can do a piece of work in 12 days and B in 15 days. They work together for 5 days and then B left. The days taken by A to finish the remaining work is

A right circular cone has base radius 9 cm and its height is 36 cm. A section is made by a plane parallel to its base through a height of one third the height of the cone. Find the volume of the sectioned part.

A tank is normally filled in 10 hrs but it takes 2 hrs longer to fill because of a leak in its bottom. If the cistern is full, in how many hours will the leak empty it?

A, B and C start to walk together from the same place round a circular path of length 15 km. A walks at the rate of 5 km/hr, B at the rate of 3 km/hr and C, at the rate of $5\over 2$ km/hr. They will meet at the starting place at the end of-

A boat covers 16 km upstream and 24 km downstream in 4 hrs, while it covers 24 km upstream and 16 km downstream in 4$1 \over 2$ hrs. The speed of the current is-

At a certain rate of simple interest, A lends Rs. 5000 to B for 2 years and Rs. 2000 to C for 4 years and receives a total interest of Rs. 900 from them. The rate of interest per annum was-