

InterviewSolution
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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. |
Answer» 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 - X = [10 8 5] 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 – Y =\(\begin{bmatrix} 99.60 \\[0.3em] 41.60 \\[0.3em] 54 \end{bmatrix}\) 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 8 5] \(\begin{bmatrix} 99.60 \\[0.3em] 41.60 \\[0.3em] 54 \end{bmatrix}\) ⇒ 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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