(a) A man purchased 180 copies of a book at N250.00 each. He sold y copies at N300.00 each and the rest at a discount of 5 kobo in the Naira of the cost price.

If he made a profit of N7,125.00, find the value of y.

(b) A trader bought x bags of rice at a cost C = 24x + 103 and sold them at a price, S = \(\frac{x^2}{20} - 33x\).

Find the expression for the profit (i) If 20 bags of rice were sold,

(ii) calculate the percentage profit.