Question

A person sells an item for Rs56 and earns as many percent of profit as CP numerically is?

Find CP and profit%

Answer 1

Let the cost price of item be X
then profit=(X)x(X/100)=X^2/100
selling price=cost price+profit
X^2+100X-5600=0
X^2+140X-40X-5600=0
X(X-40)+140(X-40)=0
(X-40)(X+140)=0
X=-140,X=40
since cost cannot be negative hence use X=40
So cost price=40
and profit=X^2/100
=40^2/100
=16%