Aptitude - Volume and Surface Area
Overview Exercise "It takes a very long time to become young."
- Pablo Picasso
6.
A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks by 1 cm when a man gets on it. The mass of the man is:
Answer: B
Explanation:
Volume of water displaced
= (3 x 2 x 0.01) m3
= 0.06 m3 .
= Volume of water displaced x Density of water
= (0.06 x 1000) kg
= 60 kg.
7.
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:
Answer: D
Explanation:
Total volume of water displaced = (4 x 50) m3 = 200 m3 .
200
40 x 20
8.
The slant height of a right circular cone is 10 m and its height is 8 m. Find the area of its curved surface.
Answer: A
Explanation:
l = 10 m,
h = 8 m.
So, r = l 2 - h 2 (10)2 - 82 = 6 m.
rl = (2 = 602 .
9.
A cistern 6m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is:
Answer: B
Explanation:
Area of the wet surface
= [2(lb + bh + lh ) - lb ]
= 2(bh + lh ) + lb
= [2 (4 x 1.25 + 6 x 1.25) + 6 x 4] m2
= 49 m2 .
10.
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:
Answer: A
Explanation:
Clearly, l = (48 - 16)m = 32 m,
b = (36 -16)m = 20 m,
h = 8 m.
3 = 5120 m3 .
Mass of man
m 0.25 m = 25 cm.
m2