A Maths Question

Let the selling price of an egg be s and the cost of each egg be c

as "The selling price of a dozen of eggs is equal to the cost price of 15 eggs",

12s=15c
s=15/12 c=5/4 c =1.25c

The percentage profit
=(selling price- cost)/ cost x 100%
=(1.25c-c)/c x 100%
=0.25c/c x 100%
=0.25 x 100%
=25%

2009-06-26 14:10:07 補充：
The number of imported apples after a quarter
= 25000 x (1+1.5%)
= 25,375

The number of imported apples after half a year
= The number of imported apples after a quarter x (1+ 1.5%)
= 25,375 x (1+1.5%)
= 25,755

Q: The selling price of a dozen of eggs is equal to the cost price of 15 eggs. Find the percentage profit.
Please answer this question in detail step by step, thanks for your help!
20points for this question, thanks~
Sol
(1/12-1/15)/(1/15)*100%
=60*(1/12-1/15)/[60*(1/15)]*100%
=(5-4)/4*100%
=25%