Question 195058
sol:
let the cost price of an article be 100 rs
selling price of an article be x rs
gain%=10%
gain% (or) profit%= (profit/c.p)*100
profit=selling price-cost price
      = x-100
substitute this value in the above formula
profit%=(x-100)
        -------  * 100
          100   
       =x-100
according to the problem profit% is 10%
10=x-100
adding 100 on both sides
10+100=x-100+100
x=110
selling price of an article=110
according to the problem double the selling price=2*110=220
profit=selling price-cost price
profit=220-100=120
double the selling price profit=120 rs