Question

A person has Rs. 35,000 that he has divided into three investments. Part of the

money is invested in a savings account with annual rate of interest of 6%, part in

7% annual yield bonds, and the remainder in a business. In 2006, when he lost 6%

of the money that he invested in that business, his net income from all three

investments was Rs. 660. If he invested Rs. 3,000 more in the business than in

savings account, how much was invested in each? Use matrix method.​

Answer 1

Answer:

It is given that Rs.30,000 must be invested into two types of bonds with 5% and 7% interest rates.

Let Rs.x be invested in bonds of the first type.

Thus, Rs.(30000−x) will be invested in the other type.

Hence, the amount invested in each type of the bonds can be represented in matrix form with each column corresponding to a different type of bond as :

X=[

x

30000−x

]

A) Annual interest obtained is Rs.1800.

We know, Interest=

100

PTR

Here, the time is one year and thus T=1

Hence, the interest obtained after one year can be expressed in matrix representation as -