# The bookshop of a particular school has 10 dozen chemistry books, 8 dozen physics books,

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.

Solution:

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}{lll}10 & 8 & 10\end{array}\right]$$\left[\begin{array}{l}80 \\ 60 \\ 40\end{array}\right]$

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

$=12(800+480+400)$

$=12(1680)$

$=20160$

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