Get busy calculating the percentage in these questions

By M.Venkat,
Director
MVK Publications
Dilsukhnagar
7671002120

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

1. An epidemic broke out in a village in which 5% of the population died. Of the remaining, 20% fled out of panic. If the present population is 4655, then the population of the village originally was?

a) 5995 b) 6125 c) 5955 d) 6000

Ans: b

Solution:

Let original population of village = x

x × 95/100 × 80/100 = 4655
x = 6125

2. The value of equipment depreciates 20% each year. How much less will the value of the equipment be after 3 years?

a) 50% b) 48.8% c) 58.8% d) 40%
Ans: b

Solution:
Let the present worth of the equipment = Rs 100

= 100 (1 – 20/100)3
= 100 × (80/100)3
= Rs 51.2
Depreciation = 100 – 51.2 = 48.8%

3. A bacterial population increases at the rate of 6% in the first 10 minutes and then 10% in the next 10 minutes. What is the overall percentage increase in the population at the end of 20 minutes?

a) 16.3% b) 16.6% c) 16.5% d) 16%
Ans: b

Solution:
The overall percentage increase in the population

Let the present population of bacteria = 100

100( 1 6/100)(1 10/100)

100 × 106/100 × 110/100 = 11660/10 = 116.6%
The overall percentage of bacterial at the end of 20 minutes \\= 116.6 – 100\\= 16.6%

4. The population of a town increased by 10% and 20% in two successive years, but decreased by 25% in the third year. Find the ratio of the population in the third year to that of 3 years ago.

a) 99 : 100 b) 100 : 99 c) 1 : 2 d) 2 : 1

Ans: a

Solution:
Let the present population of a town = 100

= 100( 1 10/100)( 1 20/100) (1 – 25/100)

= 100 × 110/100 × 120/100 × 75/100

= 99

Required ratio = 99:100

5. In a factory, the production of cycles rose to 48,400 from 40,000 in 2 years. The rate of growth per annum is?

a) 9% b) 9.5% c) 10% d) 10.5%
Ans: c

Solution: 48,400 = 40000(1 R/100)2

(1 R/100)2 = 48,400/ 40000

= 121/100

(1 R/100)2 = (11/10)2

1 R/100 = 11/10
R/100 = 11/10 – 1

R = 1/10 × 100 = 10%

6. From 1990 – 2000, the population of a country increased by 20%. From 2000 – 2010, the population of a country increased by 20%. From 2010 – 2020, the population of a country increased by 20%. The overall increased population (in percentage) of the country from 2010 – 2020 is?

a) 72.8% b) 75% c) 75.8% d) 72%
Ans: a

Solution:

100 (1 20/100)(1 20/100)(1 20/100)
100 × 6/5 × 6/5 × 6/5
= 172.8%
Required answer = 172.8 – 100 = 72.8%

7. In an election, a candidate got 62% of the total votes and won the election by 35640 votes. What is the total number of votes cast, if no vote is declared invalid?

a) 1,48,500 b) 1,48,000 c) 1,48,750 d) 1,48,250

Ans: a

Solution: 100 %

Winner Loser

62% 38%

Majority = 62 – 38 = 24%
24% = 35640

100 % = ?

? = 35640 × 100/24

= 1,48,500

8. In an election, there were only two candidates. The losing candidate got 48% of the total votes. His opponent got 6000 votes more and won by a margin of 3% votes. What was the number of invalid votes?

a) 1500 b) 2000 c) 1750 d) 2250

Ans: b

Solution: Let total votes = 100%

Winner Loser

52% 48%
Majority = 4%
But as per question = 3%
It means that 1% votes are invalid

3% ——- 6000

1% ——- ?
6000/3 = 2000

To be continued…