Calculating Net Operating Income! Help!

Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units):

Sales $ 45,000

Variable expenses 31,500

Contribution margin 13,500

Fixed expenses 8,640

Net operating income $ 4,860

6. If the selling price increases by $2 per unit and the sales volume decreases by 100 units, what would be the net operating income?