CAT Quantitative Aptitude Preparation needs time as candidates first have to clear the basics. To solve the questions based on topics like Simple Interest and Compound Interest, you must have basic knowledge. Candidates planning to appear for CAT 2021 are advised to prepare for this section and learn the tricks to calculate SI and CI. Though the chapter seems simple and only a few formulas are there in this topic but when asked in combination with other topics the questions could be tricky also. Download CAT QA Question Papers

CAT Quantitative Aptitude question paper will have MCQ and TITA type questions. To solve these questions CAT Formulas and some shortcut tricks could prove to be very helpful. Read the article to know more about CAT QA Simple and Compound Interest, important formulas and solved sample questions.

Quick Links

• CAT Previous Year Question Papers of VARC
• CAT Previous Year Question Papers of DILR

Based on the primary amount that one needs to pay to their lender, simple interest is calculated. Here, the amount that is borrowed is considered as the primary amount. With the help of borrower’s on time, the lender is ready to lend the borrowers a certain amount of money that is calculated based on the primary amount as an interest. And the interest is calculated by using a simple formula which is called simple interest.

CAT QA Simple Interest & Compound Interest Important Formulas

Compound interest can be defined as an interest which is added as extra to the primary amount of a loan or deposit on interest. 

• Principal = P
• Rate = R% per annum
• Time = n years
• Simple interest formula: (P * R * T)/100
• The overall repayable amount is (A) = P + SI (Simple Interest)
• In a situation where the interest is compounded Annually:
  • Amount = P (1 + R/100)n
• In a situation where the interest is compounded Half Yearly:
  • Amount = P (1 + (R/2)/100)2n
• In a situation where the Interest is compounded Quarterly:
  • Amount = P (1 + (R/4)/100)4n
• In a situation where the interest is compounded Annually but the time is in fraction, say 3 2⁄5 years
  • Amount = P ( 1 + R/100) 3* [ 1 + (2/5)R/100]
• In a situation where the rates are different for different years, for example R1%, R2%, R3% for 1st, 2nd, and 3rd year respectively.
  • Then Amount = P ( 1 + R1 /100) ( 1 +R2 / 100) (1 + R3 / 100)
• In a current situation where the worth of Rs. x due n years and so it is given by:
  • The current Worth =X/((1+R/100) )

CAT QA Simple Interest & Compound Interest: Solved Paper of Previous Year

Here, in the section below, some solved papers from the previous year are mentioned. 

• Ques. What is the principal invested when the compound interest is earned at the end of the terms of three year for INR 1556. Based on some money, it is earned. And at the end of two years it was INR 880. 

1. Rs. 2,400
2. Rs. 2,800
3. Rs. 2,000
4. Rs. 1,600

Correct Answer: 3

2. Ques. A certain amount of INR P with r% compound interest was deposited by Ram. In 20 years, it reached INR 16. Find out the correct sum of money when he invests the same money at r% of simple interest for 20 years. 

1. Between Rs. 2P and 2.5P
2. Between Rs. 2.5P and 3P
3. Between 3P and 3.5P
4. Between 3.5P and 4P

Correct Answer: 4

3. Ques. Based on the simple interest, an interest of 600 for 2 years is earned by Ram. Find out the interest rate when he earns INR 630 at the same interest rate and based on the compound interest rate. 

1. 5%
2. 20%
3. 30%
4. 10%

Correct Answer: 4

4. Ques. Ram earns his daily wage by selling onions in the streets of Chandni Chowk. Because of some recent shortfall in the supply of onions, the selling price of onion was doubled but the cost price remains the same because of the contract regarding the fixed price. Soon after, he found the profits had tripled. What is the original profit in percent?

1. 200/3%
2. 100%
3. 120%
4. 105∗1/3%

Correct Answer: 2

5. Ques. There are three statements followed by some questions. Go through all the following statements and mark the correct one. What is the percentage for the discount given?

26. I) On selling the table, for INR 12650, the profit of 26.5 %, was earned.
27. II) Without any discount, 30% can be earned as profit.

III) In the table, the cost price was INR 10000

1. Only I and II
2. Only II and III
3. Only I and III
4. Any two of the above
5. None of these

Correct Answer: 1

Quick Links:

6. Ques. There were some questions from topics in a practice paper at 2iim.com. Out of the total candidates who appeared in the test, 10% qualified in all topics whereas around 10% of candidates did not clear in any topics. Remaining 20% of candidates got through only in one topic. On the other hand, 25% of candidates passed in the only two topics. What is the total number of candidates who appeared in the test when around 24% of candidates qualified in only 4 topics whereas around 500 candidates passed only in 3 topics?

1. 2500
2. 2000
3. 1600
4. 4545

Correct Answer: 1

7. Ques. The strength of tensile for a material A is considered as a multiple of the amount of materials a, b, c, d used. Find out the overall change that can be seen in tensile strength of A when the amount of material of a, b, c, d are changed by +30%, -30%, -25%, +25% respectively?

1. No Change
2. +14.68%
3. –14.68%
4. Depends on the initial amount of a, b, c, d

Correct Answer: 3

8. Ques. There is a bucket which contains “a” number of small and large balls. And from which the colour of b% of balls are black. From the small balls around, c% of balls are black in colour whereas d% of balls are in black colour. What is the total number of small balls that are in the bucket? 

1. a * (b−d)/c+b−d
2. a * (b−d)/c+b−2d
3. a * (c−b)/b−d
4. a * (b−d)/c−d

Correct Answer: 4

9. Ques. A moneylender charges 50% interest to the poor people as an advantage in the most difficult situations. No one caught him as he gives 20% of his overall capital as a bribe. The capital contains initial capital and profit. What amount of bribe he needs to give at the end of the 2nd year when in the beginning of the fourth year, his capital of investment is INR 25,000?

1. Rs 4,900
2. Rs 5,200
3. Rs 5,000
4. Rs 6,000

Correct Answer: 2

10. Ques. In a test, around 35% of candidates did not qualify in the section of quantitative aptitude whereas around 42% of candidates did not qualify in the verbal section. On the other hand 14% did not pass in both the topics. What is the number of candidates who sat for the test when the number of 222 candidates qualified in both the topics?

1. 500
2. 600
3. 700
4. 800

Correct Answer:2

Quick Links:

11. Ques. When a solid cube that is made of steel is melted and also recasted for its length, breadth and height. All three have changed to +10%, +10%, -20%. Find out the change of the surface area of this cube in percentage?

1. No Change
2. +1%
3. +2%
4. -1%

Correct Answer:4

12. In a local election, around 2400 people were there to vote either for Party A or Party B. As per the survey, Party A was bound to win the election. On the day of the Election, 1/3 of the voters of Party A were kidnapped by some gang. Party B was responsible to influence the voters from the Party A voters. In this way, it helps to double the strength of its voters. And thus, Party A lost by a majority. It was half of that portion where it might have won the elections that had been fair. What is the number of the people that voted for both Party A and Party B?

1. 600(A), 1200(B)
2. 300(A), 600(B)
3. 450(A), 900(B)
4. 600(A), 900(B)

Correct Answer: 1

13. Ques. At present, there is a band which was to give their performance in India. But it received a huge amount of criticism because of the ticket which is high in price. Because of the criticism, a discount that is tabulated below is offered by the concerned authority. 

There was a rate of INR 25,000 per ticket. Other tickets from the list mentioned above are billed at the original price. What is the price for the maximum average ticket that will have to pay when a college group likes to buy only 13 tickets?

1. 23,375
2. 23,367
3. 23,380
4. 23,400

Correct Answer: 2

14. Around 30% of Vanilla-flavored ice-cream is produced in an ice-cream factory. It is mixed up with around 40% of total Banana-flavored ice-cream production. The ratio of it is 1:1. What is the total percentage of ice-cream production that can be mixed up with each other? 

1. 17.14%
2. 34.28%
3. 35%
4. More information required

Correct Answer:2

15. Ques. Hari decides to visit London and therefore prepares a budget. In London, he spends around 12% of his overall budget on the first 10% days of his travel in the time of his stay. It is known to him that he can spend another 35% of the entire day in the city. And after which he wants to travel to the countryside. What is the minimum decrease in spending in the countryside? The percentage must be counted as a percentage of his total spending in the city to complete his entire travel based on the primary budget?

1. 33.33%
2. 30.3%
3. 25%
4. 32.23%

Correct Answer: 2

16. Ques. In a field, there are two workers who are engaged in planting trees. After a while, there is a third worker who is added. After that, the number of trees which are planted is turned into half as large. What are the number of trees that can be planted by the second worker plant same as the percentage of the number of trees that was planted with the help of the first worker when the effectivity of the 2nd worker is ⅓ of the first and the third worker?

1. 65%
2. 60%
3. 70%
4. 75%

Correct Answer: 2

17. Ques. There was a burger eating competition where A, B and C participated in this. In the competition, C was beaten by C by 18 burgers. On the other hand, A also beat B by having around 50% of burgers, which is more than B. And, B had eaten only 5 percentage points by having a burger that is more than C. What is the total number of burgers that were eaten?

1. 90 burgers
2. 81 burgers
3. 72 burgers
4. 100 burgers

Correct Answer: 1

Quick Links: