A wholesaler bought 1200 pens/radios for Tk.18 each. He sold 60% of the pens for Tk.30 each and remaining for Tk.15 each. What was his average profit per pen/radio?

প্রশ্নঃ A wholesaler bought 1200 pens/radios for Tk.18 each. He sold 60% of the pens for Tk.30 each and remaining for Tk.15 each. What was his average profit per pen/radio?