The mass of 4 children, Jean, Kylie, Caden and Fabian were taken. Only 3 children can be weighed at one time. Jean, Kylie and Caden weighed a total of 148 kg. Kylie, Caden and Fabian weighed a total of 49 kg. Jean, Caden and Fabian weighed a total of 144 kg. Jean, Kylie, and Fabian weighed a total of 115 kg. What is the average mass of the 4 children?
Jean + Kylie + Caden = 148 --- (1)
Kylie + Caden + Fabian = 49 --- (2)
Jean + Caden + Fabian = 144 --- (3)
Jean + Kylie + Fabian = 115 --- (4)

(1) + (2) + (3) + (4)
3(Jean + Kylie + Caden + Fabian) = 148 + 49 + 144 + 115
3(Jean + Kylie + Caden + Fabian) = 456
Jean + Kylie + Caden + Fabian = 456 ÷ 3 = 152

Total mass of the 4 children = 152

Average mass of the 4 children
= 152 ÷ 4
= 38

Answer(s): 38 kg