Calculate the percentage of these questions

This article is in continuation to the last article focusing on the percentage topic. Here are some practice questions along with solutions that will help you in your preparation for the State government recruitment jobs.

1. If each side of a cube is decreased by 20%, then the percentage decrease in its volume is?

a) 44% b) 44.5%
c) 48.8% d) 48%

Ans: c

Solution: 20% = -20/100 = -1/5
Volume = (Side)³
Side —> 5 : 4
Volume —> 5³ : 4³
125 : 64

– 61/125 × 100% = – 48.8%

2. If the length, breadth and height of a cuboid increased by 10%, 20% and 30% respectively, then the volume of a cuboid is increased by?

a) 104% b) 114% c) 124% d) 134%

Ans: d

Solution:
10% = 10/20 = 1/2,
20% = 20/100 = 1/5,
30% = 30/100 = 3/10
Volume = length × breadth × height
Length —> 2 : 3
Breadth —> 5 : 6
Height —> 10 : 13
Volume —> 2 × 5 × 10 : 3 × 6 × 13
50 : 117

67/50 × 100% = 134%

3. If the length of a cuboid is increased by 10%, breadth is increased by 20%, and the height is decreased by 20%, then the volume of a cuboid is increased/ decreased by?

a) 5.6% increases
b) 5.6% decreases
c) 6.5% increases
d) 6.5% decreases

Ans: a

Solution:
10% = + 10/100 = + 1/10, 20% = + 20/100 = + 1/5,
20% = -20/100 = -1/5
Volume = length × breadth × height
Length —> 10 : 11
Breadth —> 5 : 6
Height —> 5 : 4
Volume —> 10 × 5 × 5 : 11 × 6 × 4
125 : 132

7/125 × 100% = 5.6%
= 5.6% increases

M Venkat
Director
MVK Publications
Dilsukhnagar
7671002120