Question

3 persons A,B,C go to stationary shop and If person A buying 10 dozen notebooks and 4 dozen pen and 5 dozen pencil and person B purchase 8 dozen notebook, 6 dozen pens and 7 dozen pencil, and person C purchase 10 dozen notebook, 5 dozen pen and 11 dozen pencil. A note book cost Rs.3, A pen cost Rs.2 and pencil cost Rs.1, by using matrix multiplication to calculate each individual will.

Answer 1

$\begin{array}{c}A=10N+4Pen+5PN=Rs3\Rightarrow 12N=Rs36\\ B=8N+6Pen+7PPen=Rs2\Rightarrow 12Pen=Rs24\\ C=10N+5Pen+11PP=Rs1\Rightarrow 12P=Rs12\\ \left[\begin{array}{c}A\\ B\\ C\end{array}\right]=\left[\begin{array}{c}1045\\ 867\\ 10511\end{array}\right]\left[\begin{array}{c}36\\ 24\\ 12\end{array}\right]\\ A=10\times 36+4\times 24+5\times 12=360+96+60=Rs516\\ B=8\times 36+6\times 24+7\times 12=288+144+84=Rs516\\ C=10\times 36+5\times 24+11\times 12=360+120+132=Rs612\end{array}$