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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.
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Solution
The number of books in the school is as follows:
Chemistry: 10 dozen = 120 books
Physics: 8 dozen = 96 books
Economics: 10 dozen = 120 books
This can be expressed as matrix A = [120 96 120].
The selling price of each book of Chemistry, Physics and Economics is Rs 80, Rs 60 and Rs 40, respectively.
This can be expressed as matrix R = `[(80),(60),(40)]`.
∴ Amount received, AR = `[120 96 120] [(80),(60),(40)]`
= 120 × 80 + 96 × 60 + 120 × 40
= [9600 + 5760 + 4800]
= [20,160]
So, the total amount received = Rs 20,160.
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