The heights of a cone and a cylinder are equal. The radii of their bases are in the ratio 2 : 1. The ratio of their volume is

• 4 : 3

• 3 : 4

• 2 : 1

• 1 : 2

102.

A spherical lead ball of radius 6 cm is melted and small lead balls of radius 3 mm are made. The total number of possible small lead balls is:

• 4250

• 4000

• 8005

• 8000

If   then r : h is 

• 17 : 8

• 8 : 17

• 8 : 15

• 15 : 8

The length (in metres) of the longest rod that can be put in a room of dimensions 10 m x 10 m x 5 m is

• 

• 15

• 

• 

The volume (in m³) of rain water that can be collected from 1.5 hect of ground in a rainfall of 5 cm is

• 75

• 750

• 7500

• 75000

A river 3 m deep and 40 m wide is flowing at the rate of 2 km/h. How much water (in litres) will fall into the sea in a minute?

• 400000

• 4000000

• 40000

• 4000

A hemisphere and a cone have equal bases. If their heights are also equal, the ratio of their curved surfaces will be

• 

• 

• 1 : 2

• 2 : 1

Marbles of diameter 1.4 cm are dropped into a cylindrical beaker containing some water and are fully submerged. The diameter of the beaker is 7 cm. Find how many marbles have been dropped in it, if the water rises by 5.6 cm.

• 50

• 150

• 250

• 350

Water is flowing at the rate of 3 km/h through a circular pipe of 20 cm internal diameter into a circular cistern of diameter 10 m and depth 2 m. In how much time will the cistern be filled?

• 1 h

• 1 h 40 min

• 1 h 20 min

• 2 h 40 min

The total surface area of a sphere is  square unit. The volume of the sphere is

•  cu unit.

• 

• 

•