# Average

1. The cost of painting the whole surface area of a cube at the rate of 13 paise per sq.cm is Rs. 343.98. Then the volume of the cube is:

(a) 8500

(b) 9000

(c) 9250

(d) 9261

Answer:  (d)

Explanation: 2. The edges of a cuboid are in the ratio 1:2:3 and its surface area is 88 the volume of the cuboid is:

(a) 120 cm³

(b) 64 cm³

(c) 48 cm³

(d) 24 cm³

Answer: (c)

Explanation: 3. 12 spheres of the same size are made from melting a solid cylinder of 16 cm diameter and 2 cm height. The diameter of each sphere is: [SSC Grad. 2000]

(a) 2 cm

(b) 4 cm

(c) 3 cm

(d) 5 cm

Answer: (b) 4 cm

Explanation: 4. 20 spheres, each of radius 10 cm are melted and casted into cones of height 20 cm and radius of base as 10 cm. The number of such cones that can be casted from the metal is

(a) 20

(b) 30

(c) 40

(d) 50

Answer: (c) 40

Explanation: 5. A hemispherical basin 150 cm in diameter holds water one hundred and twenty times as much as a cylindrical tube. If the height of the tube is 15 cm, then the diameter of the tube (in cm) is:

(a) 23 cm

(b) 24 cm

(c) 25 cm

(d) 26 cm

Answer: (c)

Explanation: 6. A right circular cylindrical tank has the storage has the capacity of 38808 ml. if the radius of the base of the cylinder is three-fourth of the height, what is the diameter of the base?

(a) 28 cm

(b) 56 cm

(c) 21 cm

(d) 42 cm

Answer: (d)

Explanation: 7. If the area of the base of a right-circular cone is 3850 and its height is 84 cm, then curved surface area of the cone is: [Bank 2008]

(a) 11000 cm²

(b) 10100 cm²

(c) 10010 cm²

(d) 10001 cm²

Answer: (c)

Explanation: 8. Total surface area of the frustum is 156π meter2 and radii are 8 and 6 meter and find the slant length?

(a) 1 meter

(b) 4 meter

(c) 8 meter

(d) 5 meter

Answer: (b)

Explanation:

R = 8 m, r = 6 m and total surface area = 156 π m²

Total surface area = π ((R2+r2) + l(R+r))

Here ‘l’ is slant height of the frustum.

156 π = π ((R2+r2) + l(R+r))

156 = (100+l (14))

14 l = 56, l = 4 meter.

9. The volume of a cuboid is twice the volume of a cube. If the dimensions of the cuboid 9 cm, 8 cm, and 6 cm, the total surface area of the cube is:

(a) 72 cm²

(b) 216 cm²

(c)  432 cm²

(d)  108 cm²

Answer: (b)

Explanation: 10. The volume of the greatest sphere that can be cut off from a cylindrical log of wood of base radius 1 cm and height 5 cm is: [Delhi police 1997]

Answer: (b)

Explanation:  