Information for two companies follows:

Skittles Company Starburst Company

Sales $ $6,000,000$ $ $4,500,000$

Contribution margin $3,600,0001,125,000$

Fixed costs $2,600,000375,000$

$(1)$ Compute the degree of operating leverage $($DOL$)$ for each company.

$(2)$ Which company is expected to produce a greater percent increase in income from a $20\%$ increase in sales?