Time to PSR     =           E x H              Where E = 10 hrs, H = 480 + 75 = 555 kts

                                    (O + H)                                                    O = 480 – 90 = 390 kts

                                                                                                O + H   = 945

                                    =            10 x 555          = 5.87 hrs at 390 kts = 2,290 nm

                                                      945