If the cost of 20 books is equal to the selling price of 18 books, then the gain percentage is:
Answer & explanation
Correct answer: option 1
Cost of 20 books = Selling price of 18 books
\(\frac{CP}{SP}\) = \(\frac{18}{20}\)
Profit% = \(\frac{20 - 18}{18}\) × 100 = $11 \frac{1}{9}$ %