PERCENTAGE & RATIO PROPORTION SET-1

Q.1 The salary of a worker was first increased by 10% & decreased by the 5%. What was the change in his salary ?

A) 4.5 %

B) 4.6 %

C) 5.5 %

D) 5.6 %

Ans. A

Shortcut:

x-y-xy/100

or 10-5-10*5/100

4.5 %

Q.2 If population of a town is increased by the 20% in the 1st year & is decreased by the 20% in the next year ,what effect can see in the population ?

A) 3 %

B) 4 %

C) 5 %

D) 6 %

Ans. B

Shortcut :

(x)2/100

Or 202/100

Or 400/100 = 4 %

Q.3 In an examination 40% of the students failed in Mathematics , 30% failed in the English & 10% failed in both. Find the % of the students who passed in both the subjects ?

A) 40 %

B) 41 %

C) 42 %

D) 43 %

Ans. A

100- (40+30-10)

= 100-(70-10)

100-60

=40% Ans.

Q.4 Due to reduction in the price of the apples by 10% a customer can buy 2kg of apples more for Rs. 180. Find the original price of the apples per kg ?

A) Rs. 13

B) Rs. 12

C) Rs. 11

D) Rs. 10

Ans. D

10% of 180 = 10/100 * 180 = 18

Therefore, Cost of 2kg of apples = Rs. 18

Cost of 1 kg of apples = Rs. 9

Let reduced price /kg = Rs.9

Let original price /kg = Rs. x

Or x-10x / 100 = 9

90x / 100 = 9

X= 10

Q.5 In a library 60% of the books are in Hindi, 50% of remaining are in English & remaining 900 are in other languages . What is the total no. of books are in English ?

A) 9000

B) 10000

C) 11000

D) 12000

Ans. A

Hindi = 20/100 X

English = 50/100*80/100 (i.e. remaining)

= 40/100 x

Now, total books

i.e. 20x/100 + 40x/100+9000 = x

On solving ,we get

X=22500

Now, to solve no. of books in English,

40/100 * 22500

= 9000