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 respectively. Find the total amount the bookshop will receive from selling all the books using matrix algebra.

Answer 1

The bookshop has $10$ dozen chemistry books, $8$ dozen physics books, and $10$ dozen economics books.
The selling prices of a chemistry book, a physics book and an economics book are respectively given as Rs $80$, Rs $60$ and Rs $40$.
The total amount of money that will be received from the sale of all these books can be represented in the form of a matrix as:

$12\left[\begin{array}{ccc}10& 8& 10\end{array}\right]\left[\begin{array}{c}80\\ 60\\ 40\end{array}\right]$

$=12[10\times 80+8\times 60+10\times 40]$

$=12(800+480+400)$

$=12\left(1680\right)$

$=20160$

Thus, the bookshop will receive Rs $20160$ from the sale of all these books.