A trust invested some money in two types of bonds. The first bond pays 10% interest and second bond pays 12% interest. The trust received Rs. 2,800 as interest. However, if trust had interchanged money in bonds, they would have got Rs. 100 less as interest. Using matrix method, find the amount invested by the trust.

Explanation

Let `x` be the first bond amount and `y` be the second bond amount.

`x xx frac{10}{100}+y xx frac{12}{100}=2800`

`x xx frac{12}{100}+y xx frac{10}{100}=2700`

`10x+12y=280000---(i)`

`12x+10y=27000----(ii)`

`AX=B`

`A=[[10, 12], [12, 10]]`

`B=[[280000], [270000]]`
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