You have been hired to manage the pension fund for Exxon Mobil and need to estimate the present value of its pension obligations which are estimated to be as follows: Annual cash flow in years 1-4: 350 million; annual cash flow in years 5-10: 485 million; annual cash flow in years 11-20 610 million, Using a 8% discount rate compounded annually, what is the present value of these annuities?