Nina is selling three types of energy bars at a market stall. She bought 60 Enerbars at 40p per bar and 200 Grainbars at 60p per bar from her normal supplier. She was also given 40 Amazebars as a promotion from a new supplier. Nina sells the bars for £2.40 and manages to sell all the Enerbars and Grainbars but only some Amazebars. She makes a profit of £542.40. How many Amazebars did she sell?