A hemispherical tank, full of water, is emptied by a pipe at the rate of 25/7 liters per sec. How much time will it take to empty half the tank if the diameter of the base of the base of the tank is 3 m?

Find the common difference of an A.P. whose first term is 5 and the sum of its first four terms is half the sum of the next four terms.

Prove that the length of tangents drawn from an external point to a circle are equal.

A drinking glass is in the shape of the frustum of a cone of height 14 cm. The diameters of its two circular ends are 4 cm and 2 cm. Find the capacity of the glass. [Use π = 22/7]

A military tent of height 8.25 m is in the form of a right circular cylinder of base diameter 30 m and height 5.5 m surmounted by a right circular cone of same base radius. Find the length of the canvas used in making the tent, if the breadth of the canvas is 1.5 m.