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Question
Jay and Ram are two friends. Jay wants to buy 4 pens and 8 notebooks, Ram wants to buy 5 pens and 12 notebooks. The price of one pen and one notebook was ₹ 6 and ₹ 10 respectively. Using matrix multiplication, find the amount each one of them requires for buying the pens and notebooks.
Solution
Let A be the matrix of pens and notebooks and B be the matrix od prices of one pen and one notebook.
Pens Notebooks
∴ A = `[(4, 8),(5, 12)]"jay"/"Ram"`
and B = `[(6),(10)]"Pen"/"Notebook"`
The total amount required for each one of them is obtained by matrix AB.
∴ AB = `[(4, 8),(5, 12)][(6),(10)]`
= `[(24 + 80),(30 + 120)]`
= `[(104),(150)]`
∴ Jay needs ₹ 104 and Ram needs ₹ 150.
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