explain it please

5) A company has variable costs that are 4/7 the value of their sales revenues. Total net income for the most recent period was a profit of $53 770 and sales were $420 000. The company has started a new marketing campaign that they hope will increase sales, but it will require additional advertising of $6 400. How many sales dollars does the company have to generate in order to remain at the same level of profitability as before the new ad campaign