any help would be greatly appreciated

A researcher surveyed 50 households to find out the number of times average family eats out every month. Through the survey, researcher has established a probability distribution of a data. X P(x) 4 6/50 5 8/50 6 10/50 7 20/50 8 6/50 a. What is the sum of all probabilities of a probability function? b. On average, how many times per month the family goes to the restaurant? Round your answer to the nearest hundredth