All Exams Test series for 1 year @ ₹349 only
Question

A sum of money at 20% rate of compound interest per annum becomes more than 100 times in n years. What is the least value of n? (Use log10 2 = 0.301, log10 3 = 0.477)

This question was previously asked in
CDS I 2023 English Previous Year Paper (16-April-2023)
The correct answer is

26

We need 1.2ⁿ > 100. Using the given logarithms, log(1.2) = 2log2 + log3 − 1 = 0.079. Thus n > 2/0.079 ≈ 25.316. The least whole number is 26.

Was this answer helpful?

Similar Questions

  1. A sum of money compounded annually doubles itself in 5 years. In how many years will it become four times of itself ?

  2. What is the principal amount which earns Rs. 210 as compound interest for the second year at 5% per annum?

  3. The rate of interest on two different schemes is the same and it is 20%. But in one of the schemes, the interest is compounded half-yearly and in the other, the interest is compounded annually. Equal amounts are invested in the schemes. If the difference of the returns after 2 years is Rs. 482, then what is the principal amount in each scheme?

  4. What is the least number of complete years in which a sum of money put out at 40% annual compound interest will be more than tripled?

  5. A merchant commences with a certain capital and gains annually at the rate of 25%. At the end of 3 years he has Rs. 10,000. What is the original amount that the merchant invested?

  6. A person borrowed Rs. 10,000 at 12% rate of interest per annum compounded quarterly for a period of 9 months. What is the interest paid by him to settle his account after 9 months?

  7. If C is the compound interest on Rs. 10,000 for one year at 4% per annum when compounded quarterly, then which one of the following is correct ?

Important Questions from Compound Interest

  1. A person borrowed Rs. 10000 on compound interest at the rate of 40 percent per annum. If the interest is compounded half yearly, then what will be the amount to be paid after 1.5 years?

  2. In how many years will a sum of Rs.1875 amount to Rs.2187 at 8 percent p.a. compound interest?

  3. A sum of money has increased by 45% in 9 years at simple interest. What will be the compound interest of Rs. 12,000 after 3 years at the same rate?

  4. At a certain rate of compound interest a certain sum amounts to Rs. 64800 in 4 years and Rs. 93312 in 6 years. What is the compound interest earned in fifth year?

  5. Karuna has an option to invest in the following three schemes. If she wants to invest Rs P, then which scheme will be most beneficial for her?

    Scheme that comes with lower interest rates and terms;

    I. 28% p.a. interest, compounded every quarter, for one year.

    II. 28% p.a. interest, compounded every half year, for one year.

    III. 28% p.a. interest, for one year, compounded every year.

Need Expert Advice?
Test Series
CDS img
Defence
UPSC CDS 2026 Mock Test Series
559 Tests 4 Tests Free
1778 Attempts
4.3(192)
English, Hindi
More Questions from CDS

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App