Practice MCQ Questions and Answer on Volume and Surface Area

1.

If the height of a right circular cone is increased by 200% and the radius of the base is reduced by 50%, then the volume of the cone :

  • (A) remains unaltered
  • (B) decreases by 25%
  • (C) increases by 25%
  • (D) increases by 50%

2.

If three equal cubes are placed adjacently in a row, then the ratio of the total surface area of the new cuboid to the sum of the surface areas of the three cubes will be ?

  • (A) 1 : 3
  • (B) 2 : 3
  • (C) 5 : 9
  • (D) 7 : 9

3.

The radius of the base and height of a metallic solid cylinder are r cm and 6 cm respectively. It is melted and recast into a solid cone of the same radius of base. The height of the cone is :

  • (A) 9 cm
  • (B) 18 cm
  • (C) 27 cm
  • (D) 54 cm

4.

Diameter of a jar cylindrical in shape is increased by 25%. By what percent must the height be decreased so that there is no change in its volume :

  • (A) 10%
  • (B) 25%
  • (C) 36%
  • (D) 50%

5.

50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 m3, then the rise in the water level in the tank will be:

  • (A) 20 cm
  • (B) 25 cm
  • (C) 35 cm
  • (D) 50 cm

6.

A metallic sheet is of rectangular shape with dimensions 48 m x 36 m. From each of its corners, a square is cut off so as to make an open box. If the length of the square is 8 m, the volume of the box (in m3) is:

  • (A) 4830
  • (B) 5120
  • (C) 6420
  • (D) 8960

7.

If the radius of the base of a right circular cylinder is halved, keeping the height same, what is the ratio of the volume of the reduced cylinder to that of the original one ?

  • (A) 1 : 2
  • (B) 1 : 4
  • (C) 1 : 8
  • (D) 8 : 1

8.

The breadth of a room is twice its height and half its length. The volume of the room is 512 cu.m. The length of the room is :

  • (A) 16 m
  • (B) 18 m
  • (C) 20 m
  • (D) 32 m

9.

A larger cube is formed from the material obtained by melting three smaller cubes of 3, 4 and 5 cm side. The ratio of the total surface areas of the smaller cubes and the larger cube is :

  • (A) 2 : 1
  • (B) 3 : 2
  • (C) 25 : 18
  • (D) 27 : 20

10.

A metallic sphere of radius 5 cm is melted to make a cone with base of the same radius. What is the height of the cone ?

  • (A) 5 cm
  • (B) 10 cm
  • (C) 15 cm
  • (D) 20 cm