Question

a person invest 2p at certain rate of simple interest after 1 ,2,and 3 year it amounted to rs 3/2p, 2p, 5/2p resp what will it amount to at end of 20 years​

Answer 1

Answer:

Given: Person invested X amount at rate of 12 %

and Y amount at rate of 10 %

Yearly interest received = Rs. 130

If investment is interchanged i.e X amount at 10 % and

Y amount at 12 %

Total interest received = Rs. 134

To calculate : X and Y .

Solution:

100

12

×X+

100

10

×Y=130 ....Equation.1

100

10

×X+

100

12

×Y=134 ....Equation.2

Multiplying Equation (1) by 5 and Equation (2) by 6, we get

0.6X+0.5Y=650 ....Equation 3.

0.6X+0.72Y=804 ....Equation 4.

Subtracting new equation, we get

(0.72−0.5)Y=154

Y=700

On substituting in Equation (3),

0.6X=650−350

X=500

He invested: Rs.500 at 12% and Rs.700 at 10 %