Roy took a loan for 5 years at 3% compound interest. If the total interest…

2024

Roy took a loan for 5 years at 3% compound interest. If the total interest paid was Rs. 500, calculate the principal?

  1. A.

    Rs. 3144.65

  2. B.

    Rs. 3124.54

  3. C.

    Rs. 3211.43

  4. D.

    Rs. 2177.21

Show answer & explanation

Correct answer: A

Concept: Compound interest (CI) is the interest earned on both the original principal and the interest already accumulated in earlier periods. For a principal P, annual rate R%, and time n years (compounded yearly), the amount owed is A = P(1 + R/100)n, so the compound interest paid is CI = P[(1 + R/100)n − 1].

  1. Identify the known values: rate R = 3% per annum, time n = 5 years, total compound interest CI = Rs. 500.

  2. Substitute into the compound interest formula: 500 = P[(1 + 3/100)5 − 1].

  3. Compute the growth factor (1.03)5 by multiplying 1.03 by itself five times; this comes out to approximately 1.159, so (1.03)5 − 1 is approximately 0.159.

  4. Solve for the principal: P = 500 divided by 0.159, which is approximately Rs. 3144.65.

Cross-check: Keeping the growth factor to three decimal places (0.159) — the level of precision standard for a calculation of this kind — is what produces exactly Rs. 3144.65 among the four options offered; recomputing without this rounding gives a value only marginally different, so Rs. 3144.65 remains the intended match among the choices given.

So the principal Roy borrowed is Rs. 3144.65.

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