Four children made the following statements.
Isaac : Aubrey is 2 kg heavier than Gavin.
Gavin : Our masses are in consecutive order.
Josiah : The average of Isaac's mass and my mass is 38 kg.
Aubrey : I am the heaviest.

What is the total mass of Josiah, Aubrey and Isaac ?
Order of the mass of 4 children:
_____ , Gavin, _____ , Aubrey (Heaviest)

Total mass of Josiah and Isaac
= 2 x 38
= 76 kg

For Josiah and Isaac,
Mass of the lighter one = 1 u
Mass of the heavier one = 1 u + 2

Total mass of Josiah and Isaac
= 1 u + 1 u + 2
= 2 u + 2

2 u + 2 = 76
2 u = 76 - 2
2 u = 74

1 u = 74 ÷ 2 = 37

The mass of the four children in consecutive order is 37, 38, 39 and 40.

Total mass of Josiah, Aubrey and Isaac
= 37 + 39 + 40
= 116

Answer(s): 116 kg