Can someone explain the formula for the below?

Can someone explain the formula for the below? A report from the marketing department indicates that a new product will generate the following revenue stream: $62,500 in the first year, $89,400 in year two, $136,200 in year three, $128,300 in year four, and $112,000 in year five.firm's discount rate is 11% and the cash flows are received at the end of each year, what is the present value of this cash flow stream is I believe $379,435.35.