The average weight of 15 athletes and three trainers is 60 kg. When four more athletes of average weight 63 kg are included in the group, what is the average weight (in kg, rounded off to the nearest integer) of the group?

61

Total weight of 15 athlete and 3 trainers = 18 × 60 = 1080 kg

After adding 4 more athlete ,

Total weight of 4 new athlete = 4 × 63 = 252 kg

Average of weight of whole group = \(\frac{1080 + 252 }{22}\) = 60.54

= 61   ( nearest integer )