Question

On a certain sum of money, after 2 years the simple interest and compound interest
obtained are Rs.400 and Rs.600 respectively. What is the sum of money invested?
(7 marks)

Answer 1

sum of money = P

Rate = R

2 years

2 years simple interest = 400 = PR2/100

= PR/50 (I)

2 years compound interest = 600

=P(1+ R/100)^2 - P

= P( 1 + R^2/50 + R^2/10000) -P

= PR/50 +P R^2/10000

= PR(1/50. + R/10000) = 600. (II)

(II) / (I) = 600/400 =( PR/50 ) / (PR(1/50. + R/10000))

3/2 = (1/50. + R/10000) /50

3/2 = 1+R/200

1/2 = R/200

R = 100

PR/50 = 400

P= 20000/100 = 200

sum invested = 400

Rate of returns = 100%

hope helpful mark brainliast if you understood it.