a realtor hopes to make at least one house sale during each calendar month (but hardly ever makes more than one). his usual success rate is a 40% chance of making at least one sale in a given month. a) what is the probability that he will make at least one sale in exactly 5 of the 12 months of next year? b) what is the probability that he will make at least one sale in no more than 4 months next year?