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Question

A sum of money invested at simple interest amounts to ₹21,500 in 5 years and ₹26,000 in 8 years. Find the principal amount (in ₹).

This question was previously asked in
RRB ALP 2025 CBT 2 Wiremen Question Paper (28-Jul-2026) (Shift 2)
The correct answer is

14,000

To find the principal amount when a sum of money is invested at simple interest, we first need to understand how simple interest works.

The formula for simple interest is:

\(SI = \frac{P \times R \times T}{100}\)

where \(SI\) is the simple interest, \(P\) is the principal, \(R\) is the rate of interest per annum, and \(T\) is the time in years.

The amount \(A\) received at the end of the period is given by:

\(A = P + SI\)

Given two scenarios:

  1. The sum amounts to ₹21,500 in 5 years.
  2. The sum amounts to ₹26,000 in 8 years.

We need to find \(P\), the principal amount.

Now, calculate the simple interest for 3 years as the difference (8 years - 5 years):

The difference in amounts = ₹26,000 - ₹21,500 = ₹4,500

This difference is the simple interest for 3 years.

So, \(SI = \frac{P \times R \times 3}{100} = ₹4,500\)

Further simplifying, we will find the interest for 1 year:

Interest for 1 year = ₹4,500 / 3 = ₹1,500

Now, compute the total interest for 5 years:

Total interest for 5 years = ₹1,500 × 5 = ₹7,500

Therefore, the principal \(P\) can be determined by:

Principal \(P = A - SI = ₹21,500 - ₹7,500 = ₹14,000\)

Thus, the principal amount is ₹14,000. Hence, the correct answer is ₹14,000.

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Similar Questions

  1. The simple interest earned on a certain sum of money for 3 years at 15% per annum is ₹2,700. Find the sum.

  2. The interest earned on Rs. 1,600 at the rate of 5% simple interest per annum for 6 years would be:

  3. A sum of money was invested at the rate of 7.5% simple interest per annuum for 4 years. If the investments were for 5 years, the interest earned would have been Rs. 375 more. What was the initial sum invested?

  4. At 9.5% simple interest per annum, a sum of money became Rs. 942 in 6 years. The sum invested initially was:

  5. Rs. 750 invested for 3 months gave an interest of Rs. 18. What was the simple rate of interest per annum?

  6. The interest earned on Rs. 2250 at the rate 3% simple interest per annum for 2 years will be:

  7. At 12% simple interest per annum a sum of money becomes Rs. 295 in \(1\frac{1}{2}\) years. What was the sum invested?

  8. Rahi deposited Rs. 600 in a bank that promised 8% simple interest per annum. If Rahi kept the money with the bank for 5 years, she will earn an interest of:

  9. At 8% simple interest per annum a sum of money becomes Rs. 300 in \(2\frac{1}{2}\) years. What was the sum invested?

  10. At 5% simple interest per annum a certain sum yields a total amount of ₹2,790 at the end of 3\(\frac{1}{4}\) years. The sum invested was:


Important Questions from Simple Interest

  1. If ₹12,800 is invested in a bank for 5 years at the rate of 9% per annum simple interest. what amount is returned by the bank?

  2. Somu has borrowed ₹10,000 from a money lender with simple interest at a rate of 7% half yearly. How much amount will he pay to the money lender after 3 years?

  3. Find the Simple interest on Rs. 2,400 from 20 March 2019 to 31 may 2019 at \(6{1 \over 4}\) % rate?

  4. If the simple interest for five years is equal is 35% of the principal, that rate of interest is:

  5. A sum fetched a simple interest of Rs. 3,040 at the rate of 8% p.a in 5 years. what is the sum?

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