The cost structure of Dennis's Retall Mart is dominated by varlable costs with a contribution margin ratio of 0.31 and fixed costs of $72.120. Every dollar of sales contributes 31 cents toward fixed costs and profit. The cost structure of a competitor, Oakfield Convenience Store, is dominated by fixed costs with a higher contribution margin ratio of 0.69 and fixed costs of $552,920. Every dollar of sales contributes 69 cents toward fixed costs and profit. Both companies have sales of $1,202.000 for the year. Required: a. Compare the two companies' cost structures. b. Suppose that both companies experience a 10 percent increase in sales volume. By how much would each company's profits increase