The average weight of certain people in a family is 60 kg. If 5 new guests having weight 10%, 20%, 30% 40% and 50% respectively more than the average weight of the family join the family, then average weight of all people increased by 5 Kg. The number of persons in family after joining the guests are:

Let n be original family members. Original total = 60n. New guests weigh: 60(1.1), 60(1.2), 60(1.3), 60(1.4), 60(1.5). New total = 60n + 60(1.1+1.2+1.3+1.4+1.5) = 60n + 60(7.5) = 60n + 450. New average = (60n + 450)/(n + 5) = 65. Solving: 60n + 450 = 65n + 325, so 5n = 125, n = 25. Total after joining = 25 + 5 = 30. Since 30 is not in options, answer is None of these.