If the cost of 20 books is equal to the selling price of 18 books, then the gain percentage is:

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 08 Dec 2022 Shift 4)

Answer 1

Given:

The cost price of 20 books = Selling price of 18 books

Concept:

Gain: The amount gained by selling a product with more than its cost price.

Formula Used:

Profit = Selling price – Cost Price

Profit percentage = (Profit/Cost Price) × 100

Calculation:

Let the Selling price of one book be 10x So,

the selling price of 18 books = 180x

Cost price of 20 books = 180x

⇒ Cost price of 1 book = \(\frac{18x}{20}\) = 9x

Profit = 10x - 9x = x

Profit % = \({x\over 9x}\times 100 = {100\over 9}\:\)

Profit % = \(11\frac{1}{9}\% \)

∴ The gain percent is \(11\frac{1}{9}\% \)

Shortcut Trick

For article-based questions, if Cost article > Selling article then there is a gain.

Gain% = \(\frac{cost~article - selling~article}{selling~article} \times 100\) = \(\frac{(20 -18)}{18} \times 100\) = \(11\frac{1}{9}\% \)