Percentage - Study Mode
[#381] A number increased by $$37frac{1}{2}$$ % gives 33. The number is :
Correct Answer
(B) 24
Explanation
Solution: Let the number be x Then, $$eqalign{
& left( {100 + 37frac{1}{2}}
ight)\% ,,{ ext{of}},,x = 33 cr
& Rightarrow 137frac{1}{2}\% ,,{ ext{of}},,x = 33 cr
& Rightarrow frac{{275}}{2} imes frac{1}{{100}} imes x = 33 cr
& Rightarrow x = left( {frac{{33 imes 2 imes 100}}{{275}}}
ight) cr
& Rightarrow x = 24 cr} $$
[#382] If A's salary is 25% more than B's salary, then B's salary is how much lower than A's salary?
Correct Answer
(C) 20%
Explanation
Solution: Let B's Salary is Rs. 100. Then,
A's Salary = (100 + 25% of 100) = Rs. 125 Difference between A's Salary and B's Salary = 125 - 100 = Rs. 25 % Difference (lower) = $$frac{{25}}{{125}} imes 100 = 20\% $$ Mind Calculation Method: 100(B salary) === 25%↑ ===> 125(A salary) === 20%↓ ===> 100 (B salary) B's salary is 20% lower than A's
[#383] Population of a town increase 2.5% annually but is decreased by 0.5% every year due to migration. What will be the percentage increase in 2 years?
Correct Answer
(B) 4.04%
Explanation
Solution: Net percentage increase in Population = (2.5 - 0.5) = 2% each year. Let the Original Population of the town be 100. Population of Town after 1 year = (100 + 2% of 100) = 102. Population of the town after 2nd year = (102 + 2% of 102 ) = 104.04 Now, % increase in population = $$frac{{4.04}}{{100}} imes 100 = 4.04\% $$ Mind Calculation Method: 100 == 2% Up(1 st year) ==> 102 == 2%Up(2 nd year) ==> 104.04 % population increase in 2 years = 4.04%.
[#384] In an election between two candidates, the winner got 65% of the total votes cast and won the election by a majority of 2748 votes. What is the total number of votes cast if no vote is declared invalid?
Correct Answer
(D) 9160
Explanation
Solution: Winner gets 65% of valid votes and loser gets 35% of votes Difference between this two = 2748 (65-35)% = 2748 30% = 2748 Total number of voters, 100% = $$frac{{2748 imes 100}}{{30}}$$
= 9160
[#385] Narayan spends 30% of his income on education and 50% of the remaining on food. He gives Rs. 1000 as monthly rent and now has Rs. 1800 left with him. What is his monthly income?
Correct Answer
(A) Rs. 8000
Explanation
Solution: Narayan's saving and rent = 1000 + 1800 = Rs. 2800 Let his monthly income be Rs. 100 30% of his income he spent on education i.e. Rs. 30 Remaining = 100 - 30 = 70 50% of remaining on food = $$frac{{70 imes 50}}{{100}} = { ext{Rs}}{ ext{. 35}}$$ Now, that 35 must be equal to his saving and rent i.e. 35 = 2800 then, 1 = $$frac{{2800}}{{35}}$$ 100 = $$frac{{2800 imes 100}}{{35}} = { ext{Rs}}{ ext{. 8000}}$$ So, his income = Rs. 8000