The co-operative store of a particular school has 10 dozen physics books, 8 dozen chemistry books and 5 dozen mathematics books. Their selling prices are Rs.65.70, Rs. 43.20 and Rs 76.50 respectively. Find by matrix method, the total amount of the store will receive from selling all these items.

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 book-shop will receive from selling all the books using matrix algebra.

A person deals only two items,Cycles and scooters.He has Rs.1,20,000 to invest and a space to store at most 38 pieces.One scooter costs him Rs.12000 and a cycle costs him Rs.800.He can sell a scooter at a profit of Rs.1500 and a cycle at a profit of Rs.200.Assuming that he can sell all the items he buys,how should he invest his money in order that he may maximum his profit.Formulate the problem mathematically.