Joya paid a sum of money for purchasing 20 pens, which she recovered in full when she sold 15 of them. What was her percentage of profit or loss per pen?
Joya sold 15 pens for the price she paid for 20 of them, so she has a profit margin of 20/15 = 1.33
Let total cost price of buying 20 pens is:20x15=300Rs.
cp of one pen for joya=15 rs
selling price of one pen for joya:20rs
total profit per pen=((20-15)x100)/15=33.3333 percent is your answer
Profit=20-15 =5 Pen
let cost prize of one pen =1 Rs
then cost prize of 20 pens=20Rs
15 pens selling prize=20 pens cost prize=20 Rs