3 cells are in anaphase so 3 / 32 = 0.09375 this tells you the proportion of time spent on anaphase.
0.09375 * 1080 = 101.25 minutes for anaphase to take place.
105 - 101.25 = 3.75
(3.75 / 105) * 100 = 3.57% difference to mean time found by scientists.