Multiple choice

A sum of Rs. 10,200 is invested partly at 8% per annum and remaining at 6% per annum for 3 years at simple interest. If the total interest is Rs. 2,124, how much money was invested at 6% per annum?

  1. Rs. 4,900

  2. Rs. 5,200

  3. Rs. 4,800

  4. Rs. 5,400
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let x be the amount at 8% and (10200-x) at 6%. Interest = (x * 8 * 3)/100 + ((10200-x) * 6 * 3)/100 = 2124. Solving: 24x + 183600 - 18x = 212400, 6x = 28800, x = 4800. Amount at 6% = 10200 - 4800 = 5400.

AI explanation

The total interest rate over 3 years is 8% * 3 = 24% for the first part and 6% * 3 = 18% for the second part. Let x be the amount invested at 8%, leading to the equation 0.24x + 0.18(10200 - x) = 2124. Simplifying gives 0.06x + 1836 = 2124, so x = 4800. The amount invested at 6% is 10200 - 4800 = Rs. 5,400.

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