4. The following information was obtained from Jack Johnson, LLC, which is a manufacturing company. Sales $600,000 (selling price per unit is $20 ); Variable cost percentage is 30% of sales; fixed cost $60,000. Required: a) What is the contribution margin ratio? b) What is the Sales in dollar value at the break-even point? b) What is the number of units of sales at the break-even point? c) What is the margin of safety? d) What is the Sales in dollar value that must be attained for the company to earn anincomeof$500,000? e) What is the degree of operating leverage based on the total sales you calculated in item (d) above. f) If the percentage of sales change by 30% during the next accounting period, using the solution you obtained in item (e) above, what will be the percentage change in income, and what will be the operating income during that next accounting period