Question

The bookshop of a particular school has 10 dozen chemistry books, 8 dozen physics books, 10 dozen economics books. Their selling prices are Rs 80, Rs 60 and Rs 40 each subject respectively. Find the total amount of the bookshop will receive from selling the books using matrix algebra.

Answer 1

Let $A=[10\times 128\times 1210\times 12]$
and $B=[806040{]}^T=\left[\begin{array}{c}80\\ 60\\ 40\end{array}\right]$
Amount received by the bookseller on selling the types of books can be computed by evaluating the product AB.
Now, $AB=\left[12096120\right]\left[\begin{array}{c}80\\ 60\\ 40\end{array}\right]=[120\times 80+96\times 60+120\times 40{]}_{1\times 1}=[9600+5760+4800{]}_{1\times 1}=[20160{]}_{1\times 1}$
$\therefore$ Amount recived by the bookseller =Rs 20160