Average weight of 20 persons is 60 kg. A new person joins the group and average weight of 21 persons becomes 59 kg. What will be the weight of new person ?

41 kg 29 kg 39 kg  40 kg

39 kg

Sum of weight of 20 persons = 20 x 60 = 1200 kg Sum of weight of 21 persons = 21 x 59 = 1239 weight of new person = 1239 - 1200 = 39 kg