Hi! Could someone give explanation and show me steps for this question, please? Thank you so much!

Den's 2015 contribution margin income statement shows the following:

Sales @ $8 per unit$128,000

Less: Variable expense(96,000)

Contribution margin$ 32,000

Less: Fixed expenses(40,000)

Operating profit (loss)$ (8,000)

If Den's advertising costs increased by $6,000, by how much would sales have to increase for the company to achieve an operating profit of $4,000?