please answer question a to f with full working out

Question 5: Cost-Volume-Profit Analysis Symbolic Pty Ltd has provided the following contribution format income statement. All questions concern situations that are within the relevant range. Required: Answer each question independently, based on the original data. a. If sales decline to 7,900 units, what would be the estimated net operating income? ( 3 marks) b. If the variable cost per unit increases by $5, spending on advertising increases by $2,000, and unit sales increase by 3,400 units, what would be the estimated net operating income? ( 3 marks) c. What is the break-even point in dollar sales? (2 marks) d. Estimate how many units must be sold to achieve a target profit of $50,400. (3 marks). e. What is the margin of safety percentage, rounded to two decimal places? ( 2 marks) f. Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 15% increase in sales volume? ( 2 marks)