Calculate the percentage differences in these questions

Hyderabad: 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. A man lost 1/8th of his initial amount in the gambling after playing 4 rounds. The rule of gambling is that if he wins he will receive Rs 100, but he has to give 50% of the total amount after each round. Luckily, he won all the four rounds. The initial amount which he had started the gambling was?
a) Rs 1000 b) Rs 1250 c) Rs 1500 d) Rs 1750
Ans: c

Solution: Let the initial amount = Rs x
Round (1): x 100/2

Round (2): ((x 100/2) 100)/2 = x 300/4

Round (3): ((x 300/4) 100)/2 = x 700/8
Round (4): ((x 700/8) 100)/2 = x 1500/16

x 1500/16 = x/8

2x = x 1500

x = 1500

2. A number is increased by 20% and then again by 20%. By what percent should the increased number be reduced so as to get back the original number?
a) 30% b) 30 1/9 % c) 30 5/9% d) 31 2/9%
Ans: c

Solution: 20% = 20/100 = 1/5
5 : 6
5 : 6
36 : 25 (to get back original number)
-11/36 × 100% = -30 5/9%
3. The sum of two numbers is 520. If the bigger number is decreased by 4% and the smaller number is increased by 12%, then the numbers obtained are equal. The smaller number is?

a) 220 b) 230 c) 240 d) 250
Ans: c
Solution: Let two numbers are x, y

96% of x = 112% y

x/y = 112/96
x : y = 7 : 6

13 –>; 520

1 –>; 40

6 –>; 6 × 40 = 240

4. A number is first increased by 40% and then decreased by 25%, again increased by 15% and then decreased by 20%. What is the net increase/decrease percent in the number?
a) 3.4% increase b) 3.4% decrease c) 4.3% increase d) 4.3% decrease
Ans: b
Solution: 40% = 40/100 = 2/5, 25% = – 25/100 = -1/4,

15% = 15/100 = 3/20, 20% = -20/100 = -1/5

5 : 7

4 : 3

20 : 23

5 : 4

500 : 483

-17
-17/500 × 100% = -3.4%

=>; 3.4% decrease
5. Salary of Giri increases from Rs 274.4 to Rs 583.2 in quarter of a year such that the percentage increase in his salary is x% in each month successively. Find the value of x?
a) 38.57% b) 28.57% c) 22.57% d) 32.57%

Ans: b
Solution: 274.4 : 583.2

686 : 1458

343 : 729 –>; 3 months

Cube root 343: 729 –>; 1 month
7 : 9

2

2/7 × 100% = 28.57%

6. From 2018 to 2019, the sales of a book decreased by 80%. If the sales in 2020 were the same as in 2018, by what percent did it increase from 2019 to 2020?
a) 100% b) 200% c) 300% d) 400%

Ans: d
Solution: Sale
2018 2019 2020
100 (say) 20 100
80
80/20 ×100% = 400%
7. A mixture of 5 litres contains 10% alcohol and another mixture of 15 litres contains 20% alcohol. Find the strength of alcohol in the resulting mixture, if two mixtures are mixed together.

a) 17% b) 17.5% c) 17.75% d) 18.25%

Ans: c
Solution: 5 × 10 15 × 20/ 5 15

= 50 300/20 = 350/20

= 17.5%

8. 1 litre of water is added to 5 litres of alcohol-water solution containing 40% alcohol strength. The strength of alcohol in the new solution will be?

a) 33 1/3% b) 16 2/3% c) 20% d) 25%

Ans: a
Solution: 40% = 40/100 = 2 –>; Alcohol/ 5 –>; Mixture

Water : Alcohol

3 : 2

2/ (5 1) × 100%

= 100/3%

= 33 1/3%

To be continued
M.Venkat
Director

MVK Publications

Dilsukhnagar

7671002120