What is the math on this - I know the answer is 2000 but how???

Consider the Gadget Store monthly budget numbers below:

Cost of goods sold = 50% of sales

Advertising expenses = 10% of sales

Supplies = 5% of sales

Salaries = $4,000

Insurance = $150

Rent = $2,000

What is the forecast for Advertising expenses?

this was all the information that was provided