JAMB 1987 · UME · Q10

By selling 20 oranges for ₦1.35 a trader makes a profit of $8\%$ . What is his percentage gain or loss if he sells the same 20 oranges for ₦1.10?

Worked solution (try it first)

₦1.35 is $108\%$ of the cost price, so the cost is $1.35 \div 1.08 =$ ₦1.25.
Selling for ₦1.10 is a loss of $1.25 - 1.10 =$ ₦0.15.
As a percentage of the cost: $\dfrac{0.15}{1.25} \times 100\% = 12\%$ loss, option C.