Question

The compound interest, calculated yearly, on a certain sum of money for the second year is rs1089 and for the third year it is rs1197.90. calculate the rate of interest and the sum of money.

Answer 1

The rate of interest is 10 %.

Sum of the money = 900 rupees.

You have to use the formula for the compound interest and then find out the rate of interest by substituting the values.

After finding out the rate of interest, you can easily find the principal amount.

Compound Interest is much better than simple interest calculations.

Answer 2

Answer: 9900

Explanation:given C. I for 2nd yr =1089

C. I for 3rd yr = 1197.90

Now difference between two C. I =1197.90-1089=1089.90

Now R%=100×108.90÷1089×100=10%

Then let P =x

SI= x ×10 ×1 ÷100=x÷10

Amt= 11x÷10

P for 2nd yr =11x÷10

SI= 11x ÷100

We know that SI= CI

Given that

11x÷100=1089

x= 1089×100÷11=9900

Therefore total sum is 9900