Percentage Questions With Explanations

Question 1.

From a container having pure milk, 20% is replaced by water and the process is repeated thrice. At the end of the third operation, the milk is:
(a) 40% Pure
(b) 50% Pure
(c) 51.2% Pure
(d) 58.8% Pure

Question 2.

300 grams of sugar solution has 40% sugar in it. How much sugar should be added to make it 50% in the solution?
(a) 10 gms
(b) 40 gms
(c) 60gms
(d) 80 gms

Question 3.

The price of an article is out by 20%. to restore it to the former value, the new price must be increased by
(a) 20%
(b) 25%
(c) 16 ²/₃%
(d) 24%

Question 4.

In an Examination, A got 10% maks less than B,B got 25% marks more than C and C got 20% less and D. If A got 360 marks out of 500, the percentage of marks obtained by D was:
(a) 70
(b) 80
(c) 75
(d) 85

Question 5.

Arvind spends 75% of his income. His income is increased by 20% and he increased his expenditure by 10%. His saving is increased by:
(a) 10%
(b) 25%
(c) 37 ¹/₂%
(d) 50%

Question 6.

The price of sugar is increased by 20%. As a result, a family decreases its consumption by 25%. The expenditure of the family on sugar will be decreased by:
(a) 10%
(b) 5%

Question 7.

A building worth Rs. 133,100 is constructed on land worth Rs. 72,900. After how many years will the value of both be the same if land appreciates at 10% pa. and building depreciates at 10% pa.?
(a) 2.5

(b) 2

(d) 3

Question 8.

Salaries of A, B and C are in the ratio 1:2:3. Salary of B and C together is Rs. 6000. By what percent is salary of C more than that of A?
(a) 300
(b) 600

Question 9.

The length of a rectangle is increased by 60% By what percent would the width have to be decreased to maintain the same area?

(a) 37 ¹/₂%
(b) 60%
(c) 75%
(d) None of these

Question 10.

For a sphere of radius 10 cm, the numerical value of ty surface area is what percent of the numerical value of its volume?
(a) 24%
(b) 26.5%

(d) 45%

Solutions

Ans. 1 (C)

Let the total quantity of original milk= 1000gm.
Milk after first operation = 80% of 100= 800gm
Milk after second operation = 80% of 800= 840gm.
Milk after third operation = 80% of 640 = 512 gm
∴ Strength of final mixture = 51.2%