a. What total monthly sales revenue is required to break even if the relative sales mix is 30 percent for Product 1 and 70 percent for Product 2? (Hint: Determine the contribution margin ratio for each product.) Note: Round your answer to the nearest dollar amount. b. What total monthly sales revenue is required to earn a monthly operating income of $16,000 if the relative sales mix is 20 percent for Product 1 and 80 percent for Product 2? Note: Round your answer to the nearest dollar amount