(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.
Explanation
(a) Total cost 180 x 250
=N45,000.00
Total selling price = 300y + (180-y) x 250 x \(\frac{95}{100}\)
300y + 42750 -237.5y
= 62.5y + 42750
Profit = 62.5y + 42750 -4500
7125 = 62.5y - 2250
9375 = 62.5y
y = 150
(b)) Profit = \(\frac{x^2}{20} - 33x\) (24x+ 103)
9x - \(\frac{x^2}{20}\) - 103
(ii) Cost = 24(20) +103 = 583.00
Selling Price =33(20) - \(\frac{20^2}{20}\) = 640
Percentage profit = \(\frac{640-583}{583}\) x 100%
= 9.78%