Correct Answer - Option 4 : 33.3%
Given:
The cost price of 20 pens is equal to the selling price of 15 pens
Formula used:
Gain = selling price – cost price
Gain % = (Gain × 100)/C.P
Calculation:
Let cost price be 1 pen is Rs. x
Then, the cost price of 15 pens = Rs. 15x
The selling price of 15 pens = Rs. 20x
According to the question:
Gain = 20x – 15x = 5x
Gain % = (5x × 100)/15x
⇒ 100/3 = 33.3%
∴ The gain percent is 33.3%.