This set covers percentage, profit and loss, discounts, simple interest and compound interest, the topics that appear in almost every campus placement and bank or SSC aptitude test. Each question has a short worked solution so you can check your method, not just your answer.
How to practise: read each question and tap the option you think is correct. You will see right away whether you got it, along with a short explanation, and your score is tracked at the bottom of the screen. This set has 18 questions.
Topics covered in this set
- Percentage change and successive changes
- Profit, loss and false weights
- Marked price and successive discounts
- Simple interest
- Compound interest and CI-SI difference
Aptitude MCQs with answers and explanations
Q1. What is the value of 35% of 240 plus 20% of 180?
a) 108
b) 120
c) 126
d) 114
Q2. The price of sugar rises by 25%. By what percentage must a family reduce its sugar consumption so that its expenditure on sugar stays the same?
a) 25%
b) 22.5%
c) 20%
d) 18%
Q3. The price of a phone is first increased by 20% and then decreased by 20%. What is the net change in its price?
a) 4% decrease
b) No change
c) 4% increase
d) 2% decrease
Q4. A's salary is 25% more than B's salary. By what percentage is B's salary less than A's salary?
a) 25%
b) 24%
c) 22%
d) 20%
Q5. The population of a town is 50,000. If it grows at 10% per year, what will the population be after 2 years?
a) 60,000
b) 61,000
c) 60,500
d) 55,000
Q6. In an election between two candidates, one candidate gets 40% of the valid votes and loses by 3,000 votes. What is the total number of valid votes?
a) 15,000
b) 7,500
c) 12,000
d) 10,000
Q7. An article bought for Rs 800 is sold for Rs 920. What is the profit percentage?
a) 12%
b) 13.04%
c) 14%
d) 15%
Q8. By selling 18 pens, a shopkeeper gains the selling price of 3 pens. What is his gain percentage?
a) 16.67%
b) 20%
c) 18%
d) 15%
Q9. A trader marks his goods 25% above the cost price and then allows a discount of 12%. What is his profit percentage?
a) 13%
b) 12%
c) 10%
d) 9%
Q10. A dishonest shopkeeper claims to sell rice at cost price but uses a weight of 900 g for every 1 kg. What is his actual gain percentage?
a) 11.11%
b) 10%
c) 9.09%
d) 12.5%
Q11. Two watches are sold for Rs 990 each. One is sold at a 10% profit and the other at a 10% loss. What is the overall result?
a) No profit, no loss
b) 1% profit
c) 2% loss
d) 1% loss
Q12. Successive discounts of 20% and 10% are equivalent to a single discount of:
a) 30%
b) 28%
c) 27%
d) 25%
Q13. What is the simple interest on Rs 12,000 at 8% per annum for 3 years?
a) Rs 2,880
b) Rs 2,960
c) Rs 3,116
d) Rs 2,400
Q14. A sum of money doubles itself in 8 years at simple interest. What is the rate of interest per annum?
a) 8%
b) 10%
c) 12.5%
d) 15%
Q15. What is the compound interest on Rs 10,000 at 10% per annum for 2 years, compounded annually?
a) Rs 2,000
b) Rs 2,200
c) Rs 2,050
d) Rs 2,100
Q16. What is the difference between the compound interest and the simple interest on Rs 5,000 for 2 years at 8% per annum?
a) Rs 64
b) Rs 32
c) Rs 40
d) Rs 16
Q17. What is the compound interest on Rs 8,000 for 1 year at 10% per annum, compounded half-yearly?
a) Rs 800
b) Rs 840
c) Rs 820
d) Rs 810
Q18. A sum of money at compound interest amounts to Rs 6,050 in 2 years and Rs 6,655 in 3 years. What is the principal?
a) Rs 5,000
b) Rs 5,500
c) Rs 4,800
d) Rs 5,445
Quick revision notes
- If price rises by r%, consumption must fall by r/(100 + r) x 100% to keep expenditure the same.
- Successive changes a% and b%: net change = a + b + ab/100 (use negative signs for decreases).
- Profit% and loss% are always calculated on the cost price unless stated otherwise.
- Discount% is always calculated on the marked price.
- Equal SPs with x% gain on one and x% loss on the other always give an overall loss of x^2/100 %.
- SI = PRT/100; a sum doubles at SI in 100/R years.
- Amount at CI = P(1 + R/100)^n; for half-yearly compounding use R/2 and 2n.
- For 2 years, CI - SI = P(R/100)^2.
Frequently asked questions
What is the fastest way to solve successive percentage change questions?
Use the formula a + b + ab/100, with a negative sign for any decrease. For example, +20% then -20% gives 20 - 20 - 4 = -4%. For three changes, apply the formula to the first two and then combine the result with the third.
Why is profit percentage calculated on cost price?
Profit is the gain over what the seller invested, so the cost price is the natural base. Questions sometimes give profit as a percentage of selling price, but they say so explicitly; otherwise always divide by CP.
When does compound interest equal simple interest?
For the first year (or first compounding period) CI and SI are equal because interest has not yet been added to the principal. From the second period onwards CI is larger, and for 2 years the difference is P(R/100)^2.
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