Multiple choice

If the interest is payable quarterly, after what time will Rs.$1600$ amount to Rs. $1852.20$ at $20\%$ per annum.

  1. $3$ months
  2. $6$ months
  3. $9$ months
  4. $1$ year
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For quarterly compounding, rate r = 20/4 = 5% per quarter. Amount = 1600(1 + 0.05)^n = 1852.20. (1.05)^n = 1852.20 / 1600 = 1.157625. Since 1.05^3 = 1.157625, n = 3 quarters, which is 9 months.

AI explanation

Since interest is payable quarterly, the new rate is 20% / 4 = 5% per quarter. Using the compound interest formula, 1852.20 = 1600(1 + 5/100)^n, which simplifies to (1.05)^n = 1.157625. Solving for the number of quarters gives n = 3. Therefore, the time is 3 quarters, which equals 9 months.

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