A spherical ball of lead 3 cm in diameter is melted and recast into three spherical balls The diameter of two of these are 1.5 cm and 2 cm respectively. The diameter of the third ball is 

An open box is made of wood 3 cm thick. Its external dimensions are 1.36 m, 1.06 m and 8.3 dm. The cost of painting the inner surface of the box at 50 paise per 100 sq. cm (in Rs.) is 

The length of a hollow thick cylindrical metallic pipe is 6 cm and its total surface area including the surface at the ends is 98π sq. cm. If the outer diameter is 8 cm, then the inner diameter in cm is 

A right pyramid stands on a rectangular base whose sides are 24 cm and 18 cm and on the shorter side, the slant height is 17 cm. Find the volume of the pyramid.

A rectangular grass plot 80 m × 60 m has two roads, each 10 m wide, running in the middle of it; one parallel to length and the other parallel to breadth. Find the cost of gravelling the roads at ₹ 2 per m². 

A field is in the form of an equilateral triangle of side 100 m. A horse is tied to a vertex of the field, with a 15 m long rope. Over what area can the horse graze? 

A shuttlecock used of playing badminton has the shape of a frustum of a cone mounted on a semi sphere. The external diameters of the frustum are 5 cm and 2 cm, the height of the entire shuttlecock is 7 cm. The external surface is of the shuttlecock is:

A cylindrical container is filled with ice cream. Its diameter is 12 cm. and height is 15 cm. The whole ice cream is distributed among 10 children in equal cones having hemispherical tops. If the height of the conical portion is twice the diameter of its base, the diameter of the ice - cream cone is –