P0 P1 P2 P3 P4 P0 P1 P2 P3 P4 P0 P1 P3 P4
0 8 16 24 32 40 56 72 79 95 111 207 253 294 393

average wating time:
(8+16+24+30+(40-8)+(56-16)+(72-24)+(79-32)+(95-40)+(111-56)+(207-72)+(253-95)+(294-111))/5=166.6