To determine the percentage, we have to divide the value by the total value and then multiply the resultant by 100.
If there are successive percentage increases of a % and b%, the effective percentage increase is:
Results on population:
Let the population of a town be P now and suppose it increases at the rate of R% per annum, then:
Population after n years
Population n years ago
Results on Depreciation:
Let the present value of a machine be P. Suppose it depreciates at the rate of R% per annum. Then:
Value of the machine after n years
Value of the machine n years ago
If A is R% more than B, then B is less than A by
If A is R% less than B, then B is more than A by
Increase N by S% :
Decrease N by S%:
Q1: Peaches are now 50% more expensive at Reliance Smart Point. What percentage reduction in consumption is required to maintain peach expenditure constant?
(a) 35 %
(b) 35.50 %
(c) 33.33 %
(d) 32.50 %
Ans: (c)
If the price of a commodity increases by r%, then the reduction in consumption so as not to increase the expenditure is –
Therefore r is the increased price(i.e 50)
By using the formula:
Q2: To pass the NDA Recruitment Test, candidates must receive 290 of the aggregate marks to pass. What is the highest total of marks an applicant can receive if they receive 203 and are considered unsuccessful by 12% of their total scores?
(a) 750
(b) 725
(c) 700
(d) 675
Ans: (b)
Let’s maximum aggregate marks = x
203 + 12% of x = 290
12% of x = 290 – 203
Q3: If Yasir’s income is 20% less than Xavier’s, by what percentage does Yasir’s salary fall short of Xavier’s?
(a) 16.66 %
(b) 15.50 %
(c) 14.45 %
(d) 13.45 %
Ans: (a)
Let the salary of Yasir be 100. then,
Salary of Xavier will be 120.
Yasir less than Xavier in %,
Q4: Jason Statham could set aside 10% of his earnings. However, when his income increased by 20% two years later, he could only save the same amount as before. How much has his spending increased by percentage?
(a)
(b)
(c)
(d)
Ans: (a)
Let earlier income be 100 Rs
∴ Savings = 10% of 100 = 10 Rs
∴ Expenditure = 90 Rs
New Income = 120 Rs
Savings (same as before) = 10 Rs
∴ Expenditure = 120 – 10 = 110 Rs
∴ Increase in Expenditure = 110 – 90 = 20
Q5: Robert Pattinson is an IT professional who spends 12% of his monthly income on power, 25% of his income on food, 20% of his income on his children’s education, 30% of his income on rent, and the rest 1040 on everything else. What is the person’s monthly salary?
(a) 7500 Rs
(b) 7700 Rs
(c) 7900 Rs
(d) 8000 Rs
Ans: (d)
Let the monthly salary of the Robert be x. then,
Total spends of Robert = (30 + 25 + 20 + 12) = 87%
Remaining % = 100 – 87 = 13%
So, 13% ≡ 1040
100% ≡ x
Using the cross multiplication method,
320 videos195 docs211 tests

1. What is the formula for calculating percentages? 
2. What are some important formulas related to percentages? 
3. How is the percentage difference calculated? 
4. How can percentages be useful in reallife situations? 
5. What does the term "percentages" mean? 
320 videos195 docs211 tests


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