Question

joy bought pens at rs.120 dozen. He sold it for 15rs. each. What is his profit percent

Answer 1

Cost price of 1 pen= 120/12= 10
selling price = 15
profit of = ( 15-10)= 5
profit% =( 5/10*100)%
= 50%

Answer 2

CP of 12 pens = 120

CP of 1 pen = 120/12 = 10
__________________________

SP of 1 pen= 15

here CP < SP

so its a profit

profit = SP - CP

= 15 - 10

= 5

profit % =( 5 x 100/10)% = 50%