please show work so i can understand. thank you

6) General Mills is looking to introduce a new cereal in the marketplace. The box of cereal has a cost of $1.64 and the company historically has made 67% margin on its sale. a) What is the selling price needed to achieve the 67% margin? b) If the company has fixed costs of $240,000, how many boxes of cereal is needed to breakeven? c) If General Mills would like to make $55,000 profit, how many boxes would the need to sell