Average weight of 15 persons is 30 kg. A new person whose weight is 78 kg joins the group. What will be the average weight of 16 persons ?

31. 5 kg  34 kg 33 kg 32 kg

33 kg

Sum of weight of 15 persons = 15 x 30 = 450 Sum of weight including new person = 450 + 78 =  528 Average weight of 16 persons = 33 kg