The mass of 4 children, Raeann, Esther, Cody and Luis were taken. Only 3 children can be weighed at one time. Raeann, Esther and Cody weighed a total of 98 kg. Esther, Cody and Luis weighed a total of 68 kg. Raeann, Cody and Luis weighed a total of 150 kg. Raeann, Esther, and Luis weighed a total of 68 kg. What is the average mass of the 4 children?
Raeann + Esther + Cody = 98 --- (1)
Esther + Cody + Luis = 68 --- (2)
Raeann + Cody + Luis = 150 --- (3)
Raeann + Esther + Luis = 68 --- (4)

(1) + (2) + (3) + (4)
3(Raeann + Esther + Cody + Luis) = 98 + 68 + 150 + 68
3(Raeann + Esther + Cody + Luis) = 384
Raeann + Esther + Cody + Luis = 384 ÷ 3 = 128

Total mass of the 4 children = 128

Average mass of the 4 children
= 128 ÷ 4
= 32

Answer(s): 32 kg