burger joint paid $200 in dividends and $450 in interest expense. the addition to retained earnings is $300 and net new equity is $750. the tax rate is 30%. sales are $7000 and depreciation is $710. what are operating cash flows?

my professor has the answer listed as $1,660

he started by finding the net income= dividends+retained earnings= 200+300=$500

then went on to using this formula for operating cash flows, OCF= Depreciation+EBIT-Taxes. but he is not clear on how he recieved the answer to be $1660. please show steps and formulas. thank you