or
or
Let,
Purchase price of 12 pencil = Tk. x
Purchase price of 1 pencil = x /12
Salse price of 8 pencil = Tk. x
Salse price of 1 pencil = x/8
Profit = x/8 - x/12 = ( 3x - 2x) /24 = x/24
In the x/12 profit is Tk.x/24
In the 1 profit is Tk ( x × 12) /( 24 ×x)
In the 100 profit is Tk = ( x × 12 ×100)/ ( 24 × x) = 50
