Please with exlanation :)

4. Consider the sales revenues for a firm were $800,000, the variable expenses $750,000 and the fixed expense $30,000. Sales are expected to increase by 30%. Required: (1) Compute the degree of operating leverage. (2) Determine the percentage change in operating income. (3) Determine the expected amount of operating income. 4. Consider the sales revenues for a firm were $800,000, the variable expenses $750,000 and the fixed expense $30,000. Sales are expected to increase by 30%. Required: (1) Compute the degree of operating leverage. (2) Determine the percentage change in operating income. (3) Determine the expected amount of operating income