## 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