Mohan paid a sum of money for purchasing 30 pens, which he recovered in full when he sold 15 of them. What was his percentage of profit or loss per pen?  Select.
A) 60% B) 70% C) 80% D) 90% E) 100%
E   33.33%   If the sum he paid whilst purchasing 30 pens = A,   Then the Cost Price of each pen = A/30.   Since the amount he got whilst selling 15 pens is also = A   Then the Selling Price of each pen = A/15.   Since Selling Price &gt; Cost Price, he made a profit.   Profit per pen = Selling Price - Cost Price = A/15 - A/30 = A/30.   Profit percentage per pen = Profit per pen / Cost per pen x 100 = (A/30) / (A/30) x 100 = 100% Answer :100%
<result>E</result>
Mohan paid a sum of money for purchasing 30 pens, which he recovered in full when he sold 15 of them. What was his percentage of profit or loss per pen?