The cooperative stores of a particular school has 10 dozen physics books, 8 dozen chemistry books and 5 dozen mathematics books. Their selling prices are Rs 8.30, Rs 3.45 and Rs 4.50 each respectively. Find the total amount the store will receive from selling all the items.

Given the details of stock of various types of books.


Physics: 10 dozen books


Chemistry: 8 dozen books


Mathematics: 5 dozen books


Hence, the number of dozens of books available in the store can be represented in matrix form with each column corresponding to a different subject as -



The price of each of the items is also given.


Cost of one physics book = Rs 8.30


Cost of one dozen physics books = 12 × Rs 8.30


Cost of one dozen physics books = Rs 99.60


Cost of one chemistry book = Rs 3.45


Cost of one dozen chemistry books = 12 × Rs 3.45


Cost of one dozen chemistry books = Rs 41.40


Cost of one mathematics book = Rs 4.50


Cost of one dozen mathematics books = 12 × Rs 4.50


Cost of one dozen mathematics books = Rs 54


Hence, the cost of purchasing a dozen books of each subject can be represented in matrix form with each row corresponding to a different subject as –



Now, the amount received by the store upon selling all the available books can be found by taking the product of the matrices X and Y.



XY = [10 × 99.60 + 8 × 41.40 + 5 × 54]


XY = [996 + 331.20 + 270]


XY = [1597.20]


Thus, the total amount the store will receive from selling all the items is Rs 1597.20.


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