Question

The bookshop of a particular school has 10 dozen Chemistry books, 8 dozen Physics books, 10 dozen Economics books. Their selling prices are $₹80,₹60$ and $₹40$ each respectively. The total amount, the bookshop will receive from selling all the books using matrix algebra, is

• A. ₹ 21160
• B. ₹ 20610
• C. ₹ 26100
• D. ₹ 20160

Answer 1

Answer: (D)

Sirice, the boukstiop of a parlicular schoul has 10 dozen Chemistry books, 8 dozen Physics books, 10 dozen Economics books. Therefore, the matrix $A$ representing total number of each books is given by

Also, the selling price of each book is represented by the matrix
$B=â\begin{array}{c}80\\ 60\\ 40\end{array}â$
Amount received by the bookseller on selling all the types of books can be computed by evaluating the product $AB$.
Now, $AB=\left[\begin{array}{ccc}120& 96& 120\end{array}\right]â\begin{array}{c}l80\\ 60\\ 40\end{array}â$
$=[120×80+96×60+120×40]$
$−[9600+5760+4800]$
$\text{Â -Â [20160]Â }$
$∴$ Amount received by the bookseller is ₹ 20160 .