Question

A person invested some money at 12% and other amount at 10% simple interest. He earns a yearly interest of 1300. If he had interchanged the amount he would have received ₹40 more as yearly interest. How much did he invest at different interest?

Answer 1

Let X be the amount invested at 12 % and Y be the amount invested at 10 %.

We can write

(12x/100) + (10y/100) = 1300 - - - - - - - Eqn (1)

In the second case, changing the amount

We can write

(10x/100) + (12y/100) = 1340 - - - - - - - - Eqn (2)


Eqn(1) X 5

(60x/100) + ( 50y/100) = 6500 - - - - Eqn(3)

Eqn(2) X 6

(60x/100) + (72y/100) = 8040-------Eqn(4)

Eqn(4) - Eqn(3) = (22y/100) = 1540

Therefore Y =7000

Eqn(1) X 6

(72x/100) + ( 60y/100) = 7800 - - - - - Eqn(5)

Eqn(2) X 5

(50x/100) + ( 60y/100) = 6700--------Eqn(6)

Eqn(5) - Eqn(6) = (22x/100) = 1100

Therefore X = 5000

The Amounts are 7000 and 5000