Multiple choice

A person borrowed Rs. 9,000 at 7%, Rs. 12,000 at 8% and Rs. 15,000 at 9% simple interest per annum. He had to pay Rs. 50,700 at the end of n years. What is the value of n?

  1. 3

  2. 4

  3. 5

  4. 6
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total interest = 50700 - (9000 + 12000 + 15000) = 50700 - 36000 = 14700. Simple interest formula: I = P*R*T/100. 14700 = (9000*0.07*n) + (12000*0.08*n) + (15000*0.09*n). 14700 = (630 + 960 + 1350)n = 2940n. n = 14700 / 2940 = 5.

AI explanation

The total amount to be paid is the sum of the principals plus the simple interest on each portion, using the formula Simple Interest equals Principal multiplied by Rate multiplied by Time divided by 100. This gives the equation 36000 plus n multiplied by ((9000 multiplied by 7) plus (12000 multiplied by 8) plus (15000 multiplied by 9)) divided by 100 equals 50700. The combined interest per year is 630 plus 960 plus 1350, totaling 2940, so the equation simplifies to 36000 plus 2940n equals 50700. Solving for n gives 14700 divided by 2940, which means n is 5.

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