Problems on Ages
Problems on Ages - 1 Problems on Ages - 2 Problems on Ages - 3 Problems on Ages - 4Problems on Average
Problems on Average - 1 Problems on Average - 2 Problems on Average - 3Odd Man Out Series
Odd Man Out Series - 1 Odd Man Out Series - 2 Odd Man Out Series - 3 Odd Man Out Series - 4Problems on Percentage
Problems on Percentage - 1 Problems on Percentage - 2 Problems on Percentage - 3 Problems on Percentage - 4 Problems on Percentage - 5Permutation and Combination
Permutation and Combination - 1 Permutation and Combination - 2 Permutation and Combination - 3Problems on Probability
Problems on Probability - 1 Problems on Probability - 2 Problems on Probability - 3 Problems on Probability - 4Problems on Profit Loss
Profit and Loss - 1 Profit and Loss - 2 Profit and Loss - 3 Profit and Loss - 4 Profit and Loss - 5 Profit and Loss - 6Problems on Test Divisibility
Test Divisibility - 1 Test Divisibility - 2 Test Divisibility - 3Time and Work
Time and Work - 1 Time and Work - 2 Time and Work - 3The ones who are crazy enough to think they can change the world are the ones who do.- Steve Jobs
Percentage Questions and Answers
Percentage - Aptitude
11.Sixty five percent of a number is 21 less than four-fifth of that number.What is the number?
x
Option: B
Explanation
consider the number as x
65% of x is 21 less than 4/5 of x
i.e) 4/5 of x - 65% of x = 21
convert percentage into fractions
4/5x - 65/100x = 21
taking LCM
(80x - 65x)/100 = 21
15x = 21 * 100
x = 2100/15 = 140
Ans = 140
12.Difference of two numbers is 1660. If 7.5% of one number is 12.5% of the other number, find the two numbers.
x
Option: A
Explanation
consider the two numbers as x and y
Difference of two numbers is 1600
i.e) x - y = 1660
we can also say 7.5% of x = 12.5% of y
convert percentage into fractions
(7.5/100) * (1/10) * x = (12.5/100) * (1/10) * y
75/100x = 125/100y
75x = 125y
x = 125y/75 = 5y/3
we know that, x - y = 1660, substitute the value of x in here
5y/3 - y = 1660
(5y - 3y)/3 = 1660
y = (1660 * 3)/2 = 2490
i.e) x - 2490 = 1660
x = 1660 + 2490 = 4150
Ans = Two numbers are 2490 & 4150
13.In expressing a length 81.472km as nearly as possible with three significant digits, find the percentage error.
x
Option: A
Explanation
error = (81.5 - 81.472)km = 0.028
To find percentage error
((0.028/81.472) * 100) %= 0.034%
Ans = 0.034%
14.In an election between two candidates, 75% of the voters cast their votes,out of which 2% of the votes were declared invalid. A candidate got 9261 votes which were 75% of the total valid votes. Find the total number of votes enrolled in that election.
x
Option: D
Explanation
consider the total number of votes enrolled as x
so number of votes cast = 75% of x
also valid votes = 98% of(75% of x)
A candidate got 9261 votes which is 75% of valid votes
i.e) 75% of(98% of (75% of x)) = 9261
convert percentage into fractions
(75/100) * (98/100) * (75/100) * x = 9261
x = (9261 * 100 * 100 * 100)/(75 * 98 * 75) = 16800
Ans = 16800 votes
15.Raja's Mathematics test had 75 problems i.e) 10 arithmetic, 30 algebra and 35 geometry problems. Although he answered 70% of the arithmetic, 40% of the algebra and 60% of the geometry problems correctly, he did not pass the test because he got less than 60% of the problems right. How many more questions he would have needed to answer correctly to earn a 60% passing grade?
x
Option: C
Explanation
number of questions attempted correctly=(70% of 10 + 40% of 30 + 60% of 35)
convert percentage into fractions
((70/100) * 10) + ((40/100) * 30) + ((60/100) * 35)
7 + 12 + 21 = 40
number of questions answered correctly by raja is 40 questions
Questions to be answered correctly for 60% grade = 60% of 75
convert percentage into fractions
(60/100) * 75 = 45 questions
required number of questions = (45 - 40) = 5 questions
Ans = 5 questions
Related to Problems on Percentage
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