Cost price of 18 pens is equal to selling price of 21 pens. Find the net gain or loss% ?Question 20Answera.16.66% profitb.14.28% lossc.14.28% profitd.16.66% loss

The problem states that the cost price of 18 pens is equal to the selling price of 21 pens. This implies that the seller is selling more pens for the price he bought fewer pens, indicating a loss.

Let's denote the cost price of one pen as 'x'. Therefore, the cost price of 18 pens is 18x.

According to the problem, this is also the selling price of 21 pens. So, the selling price of one pen is 18x/21.

The loss per pen is therefore the cost price minus the selling price, which is x - (18x/21) = 3x/21 = x/7.

The percentage loss is then (loss/cost price) * 100, which is (x/7) / x * 100 = 14.28%.

So, the answer is b. 14.28% loss.