Question

a certain sum of money is invested at a rate of 10% per annum compounded interest the interest compounded annually if the difference between the interest of 3rd year and 1st year is rupees 1105 find the sum invested..Fast

Answer 1

Answer:

Principal = Rs.52,619.05

Step-by-step explanation:

Let the principal be P

compound rate of interest = 10%

for 1 yr the interest will be P * ((1+10/100)-1) = P * (1.1-1) = 0.1P

for 2 yrs the interest will be P * ((1+10/100)²-1) = P * (1.21-1) = 0.21P

Hence the interest for the 2nd yr alone is 0.21P - 0.1P = 0.11P

for 3 yrs the interest will be P * ((1+10/100)³-1) = P * (1.1³ - 1) = 0.331P

Hence interest for the 3rd yr alone will be = 0.331P - 0.21P = 0.121P

As mentioned the difference between the interest of 3rd yr and 1st yr is 1105, hence

0.121P - 0.1P = 1105

0.021P = 1105

P = 52619.05