If the selling price of 20 pens is equal to the cost price of 16 pens, then find the loss percentage.

20%

Profit = Selling price of 20 pens - Cost Price of 20 pens

But, selling price of 20 pens = cost price of 16 pens

Profit = cost price of 16 pens - cost price of 20 pens

This is a loss condition

Loss = Cost Price of 4 pens

Loss% = Cost Price of 4 pens*100/Cost Price of 20 pens = 4units*100/20units = 20%

The correct answer is Option (3) → 20%