How do I calculate the following questions on Problem 9-48 from the book "Cost Management 7th Edition, Author: Blocher, Edward"

5. Prepare a data table for the breakeven volume and percentage change in the breakeven point from the base case (requirement 3) for 1% absolute changes in sales mix for HPC-Weekly over the range 20% to 30%.

6. What sales level (in total units) at the assumed sales mix is required to reach a before-tax profit of $75,000?

7. Given the assumed sales mix, what sales volume (in total units) is required to generate an after-tax profit, A, equal to 10% of sales dollars? (Show calculations.)

Thank you!