A commuter, who caught the same rain to work everyday, kept a recod over six months and found that the train was late on 49 days out of a total of 126 working days. Use a binomial probability model to estimate the probability that, in five day working week, the train will be late exactly 3 times. State briefly, giving reasons, whether a binomial model is likely to be a satisfactory or unsatisfactory mathematical model in this situation.