Following is the last year data of X company: Selling price Variable expenses Fixed expenses for the year $180,000 $80 per unit $40 per unit The company sold 45,000-unit last year. Managers of X company believes that the sales can be doubled when expenditure on advertising is increased by $1.50 per unit, keeping the selling price same as last year. Determine the amount by which advertising can be increased with profits remaining unchanged?