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