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Question

Kumar lent an amount to Arif at a simple interest rate of 10% p.a. for 3 years, and Arif lent this amount to Naresh at a simple interest rate of 20% p.a. for 3 years. If the interest Arif received was ₹1,560 after 3 years, then what was the amount that Kumar had lent to Arif?

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
₹5,200

Simple Interest Calculation: Profit Analysis

The problem describes a scenario with two related simple interest transactions. We need to find the initial principal amount based on the profit earned by Arif.

  • Kumar lends a principal amount (P) to Arif at 10% simple interest per year for 3 years.
  • Arif then lends this same principal amount (P) to Naresh at 20% simple interest per year for 3 years.
  • Arif's net gain (profit) from these transactions is ₹1,560 over the 3 years.

Interest Calculations

Let the principal amount lent by Kumar to Arif be '$P$'.

  • The interest rate for the loan from Kumar to Arif is $R_1 = 10\%$ p.a.
  • The interest rate for the loan from Arif to Naresh is $R_2 = 20\%$ p.a.
  • The time period for both loans is $T = 3$ years.

The formula for Simple Interest (SI) is given by:

$SI = \frac{P \times R \times T}{100}$

Calculate the interest Arif pays to Kumar:

$SI_{paid} = \frac{P \times 10 \times 3}{100} = \frac{30P}{100}$

Calculate the interest Arif receives from Naresh:

$SI_{received} = \frac{P \times 20 \times 3}{100} = \frac{60P}{100}$

Principal Amount Determination

Arif's profit is the difference between the interest he received and the interest he paid:

$Profit = SI_{received} - SI_{paid}$

We are given that Arif's profit is ₹1,560:

$\frac{60P}{100} - \frac{30P}{100} = 1560$

Combine the terms:

$\frac{(60 - 30)P}{100} = 1560$ $\frac{30P}{100} = 1560$

To find the principal amount $P$, rearrange the equation:

$0.30 \times P = 1560$ $P = \frac{1560}{0.30}$ $P = \frac{15600}{3}$ $P = 5200$

The amount that Kumar lent to Arif was ₹5,200.

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Similar Questions

  1. Find the simple interest (in ₹) on ₹4,000 at 6.75% per annum rate of interest deposited on 21 February 2024 and withdrawn on 22 April 2024.
  2. Sapna invested ₹21,900 on simple interest, partly at 14% per annum and partly at 10% per annum. If she earns equal interests from the two investments after 2 years, then find the sum invested at 14% per annum (in ₹).
  3. Find the simple interest (in ₹) on ₹1,200 at an interest rate of 4% per month for 11 months.
  4. A man purchases a washing machine for $₹12,000$. He pays $₹2,000$ at first and the rest after $1\text{ year}$, on which he is charged a simple interest at the rate of $10\%$ per year. The total amount he pays for the washing machine is:
  5. Sapna invested ₹21,700 on simple interest, partly at 3% per annum and partly at 12% per annum. If she earns equal interests from the two investments after 7 years, then find the sum invested at 3% per annum (in ₹).
  6. A sum of ₹800 becomes ₹920 in 3 years at simple interest. If interest is increased by 4%, then the amount will increase to:
  7. Find the simple interest (in ₹) on ₹4,000 at 7.5% per annum rate of interest deposited on 4 February 2024 and withdrawn on 5 April 2024.
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  9. Find the simple interest (in ₹) on ₹4,000 at 7.5% per annum rate of interest deposited on 5 February 2024 and withdrawn on 6 April 2024.
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Important Questions from Simple Interest

  1. Anil lent a sum of Rs. 5,000 on simple interest for 10 years in such a way that the rate of interest is 6% per annum for the first 2 years, 8% per anmum for the next 2 years and 10% per annum beyond 4 years. How much interest (in Rs.) will he earn at the end of 10 years?

  2. What will be the simple interest on a sum of Rs. 12000 at the rate of 15 percent per annum for three years ?

  3. If in 13 years fixed sum doubles at simple interest, what will be the interest rate per year? (correct to two decimal places)

  4. On simple interest a sum of Rs. 640 becomes Rs. 832 in 2 years. What will Rs. 860 become in 4 years at the same rate of simple interest?

  5. A certain sum amounts to Rs. 81840 in 3 years and to Rs. 92400 in 5 years at x% p.a. under simple interest. If the rate of interest is becomes (x + 2)%, then in how many years will the same sum double itself?

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