Multiple choice

Ketty borrows Rs. 845 at the beginning of a year at a certain rate of simple interest. After 6 months, she borrows an additional Rs. 422.50 at twice the previous rate of interest. If the total interest on both borrowings at the end of the year is Rs. 53.50, what is the original rate of interest per annum?

  1. 4.5%

  2. 4.22%

  3. 3.16%

  4. 5%

  5. 5.25%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interest = (845 * r * 1) / 100 + (422.50 * 2r * 0.5) / 100 = 53.50. 8.45r + 4.225r = 53.50. 12.675r = 53.50. r = 4.22%.

AI explanation

Let the original rate be R percent, so the second rate is 2R percent. Using the simple interest formula, the interest on the first loan is 845 times R times 1 divided by 100, and the interest on the second loan is 422.5 times 2R times 0.5 divided by 100. The total interest is 8.45R plus 4.225R equals 53.50. Solving gives 12.675R equals 53.50, so R equals 4.22 percent. The original rate of interest per annum is 4.22%.

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