This is a managerial accounting class. The textbook is: for Introduction to Managerial Accounting 7th edition by Pete Brewer. My teacher made this question up on her own, so the steps and answer probably won't be in the book. Please show me the steps as to how you get the answer. Thank you!

Use the following to answer the next two questions: Gossen Company is planning to sell 200,000 pliers for $4.00 per unit. The contribution margin ratio is 25%.

1. If Gossen will break even at this level of sales, what are the fixed costs? a) $100,000, b) $160,000, c) $200,000, d) $300,000. I know the answer here is c) 200,000.

2. If Gossen raises it selling price by 10% and lowers it variable costs by 10%, then its contribution margin is a) remains the same, b) increaes to nearly 39%, c) decreases to around 10%. I know the answer here is b) increases to nearly 39%, but could you please show me the steps as to how you get this answer?