Question

By selling 25 articles one gains cost price of 15 articles.Find the gain percentage

Answer 1

let the costprice of each article br cp;
selling price be sp;
given 
20cp=15sp
=>cp=3/4(sp);
Total profit on each article is sp-cp=>sp-(3/4)sp=>1/4(sp);
let x be the discount % on 20 articles
then from problem
(x/100)20cp=profit of 5 articles...............(eq 1)
we know profit on single article is (1/4)sp=>5 articles is (5/4)sp
we can write eq 1 as
(x/100)20cp=(5/4)sp
=>(x/100)20(3/4)sp=5sp/4
=>3x=25;
=>x=25/3;
Discount % is 8.33
Hope this is correct