Question

The sum is invested at 10% compounded annually,on which the interest for the first year plus the interest for the third year amounts to Rs.1989. The sum invested is *​

Answer 1

Answer:

12000

Step-by-step explanation:

Let the sum be P.

Rate = 10 %

CI for 3rd year = amount at the end of 3rd year- amount at the end of 2nd year

= P (1+10/100)^3-(1+10/100)^2

= P (11/10)^3-(11/10)^2

=P (11/10)^2×(11/10-1)

= P × 121/1000

CI for 1st year = P×10×1/100 = P/100

SI = P×R×T/100

According to the question

121/1000P-P/100=252

(121-100/1000)=252

21/100P=252

P=12000/-