please do this question

I am buying a firm with an expected perpetual cash flow of $330 but am unsure of its risk. If I think the beta of the firm is zero, when the beta is really 1, how much more will I offer for the firm than it is truly worth? Assume the risk-free rate is 6% and the expected rate of return on the market is 15%. (Input the amount as a positive value.) Present value difference $