Percentage - Study Mode
[#96] A saves 20% of his monthly salary. If his monthly expenditure is Rs. 6000, then his monthly savings is :
Correct Answer
(A) Rs. 1500
Explanation
Solution: Let the salary = 100 units Savings = 20% Savings = 100 × $$frac{20}{100}$$ = 20 units Expenditure = (100 - 20) = 80 units According to the question, 80 units = Rs. 6000 1 unit xa0 xa0 = Rs. 75 Savings = 75 × 20 = Rs. 1500
[#97] A man spends 75% of his income. His income increased by 20% and he increased his expenditure by 15%. His savings will then be increased by :
Correct Answer
(C) 35%
Explanation
Solution: Let the income of the man = Rs. 100 ∴Intial Expenditure = Rs.75 Now new income become = 100 + 20% of 100 = Rs. 120 New Expenditure = 75 + 15% of 75 = Rs.86.25 Intial Saving = 100 - 75 = Rs. 25 New Saving = 120 - 86.25 = Rs. 33.75 Required percentage increase : = $$frac{(33.75 - 25)}{25}$$ xa0 × 100 = 35%
[#98] Due to fall of 10% in the rate of sugar, 500 gm more sugar can be purchased for Rs. 140. Find the original rate?
Correct Answer
(A) Rs. 31.11
Explanation
Solution: Money spent originally = Rs. 140
Less Money to be spent now = 10% of 140 = Rs. 14 Rs. 14 now yield 500 gm sugar So, Present rate of sugar = Rs. 28 per kg. If the present value is Rs. 90, the original value = Rs. 100 If the present value is Rs. 28 the original value $$ = { ext{Rs}}{ ext{. }}frac{{100}}{{90}} imes 28 = { ext{Rs}}{ ext{. }}31.11$$
[#99] Two numbers are respectively 20% and 50% of a third number. What per cent is the first number of second?
Correct Answer
(D) 40%
Explanation
Solution: $$eqalign{
& { ext{Let third number is x}}. cr
& { ext{Then}},{ ext{first}},{ ext{no}}{ ext{.}} cr
& 20\% ,{ ext{of}},x = frac{{20x}}{{100}} cr
& { ext{Second}},{ ext{number}} cr
& = 50\% ,{ ext{of}},x = frac{{50x}}{{100}} cr
& { ext{Percent of first no of second no,}} cr
& = {frac{{ {frac{{20x}}{{100}}} }}{{ {frac{{50x}}{{100}}} }}} imes 100 cr
& = frac{{ {2 imes 100} }}{{20}} cr
& = 40\% cr} $$
[#100] An empty fuel tank of a car was filled with A type petrol. When the tank was half-empty, it was filled with B type petrol. Again when the tank was half-empty, it was filled with A type petrol. When the tank was half-empty again, it was filled with B type petrol. What is the percentage of A type petrol at present in the tank?
Correct Answer
(B) 37.5%
Explanation
Solution: Let the capacity of the tank be 100 litres Initially: A type petrol = 100 litres After first operation: A type petrol = $$frac{{100}}{2}$$ = 50 litres B type petrol = 50 litres After second operation:
A type petrol = $$frac{{50}}{2}$$ + 50 = 75 litres B type petrol = $$frac{{50}}{2}$$ = 25 litres After third operation: A type petrol = $$frac{{75}}{2}$$ = 37.5 litres B type petrol = $$frac{{25}}{2}$$ + 50 = 62.5 litres Required percentage = 37.5%