A trust fund has Rs. 30,000 that must be inve | vedclass

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(A) Let the amount invested in the first bond be Rs. $x$ and in the second bond be Rs. $(30000 - x)$.Using matrix multiplication,we represent the inve

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$15000$ and $15000$

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(A) Let the amount invested in the first bond be Rs. $x$ and in the second bond be Rs. $(30000 - x)$.Using matrix multiplication,we represent the investment as a row matrix $A = [x \quad 30000 - x]$ and the interest rates as a column matrix $B = \begin{bmatrix} 0.05 \ 0.07 \end{bmatrix}$.The total interest is given by the product $AB = [1800]$.$[x \quad 30000 - x] \begin{bmatrix} 0.05 \ 0.07 \end{bmatrix} = [1800]$$0.05x + 0.07(30000 - x) = 1800$$0.05x + 2100 - 0.07x = 1800$$-0.02x = 1800 - 2100$$-0.02x = -300$$x = \frac{300}{0.02} = 15000$.Thus,Rs. $15000$ is invested in the first bond and Rs. $(30000 - 15000) = 15000$ is invested in the second bond.

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