Four children made the following statements.
Harper : The average of Mason's mass and my mass is 37 kg.
Lily : I am the heaviest.
Mason : Noah is 2 kg lighter than Lily.
Noah : Our masses are in consecutive order.

What is the total mass of Harper, Lily and Mason ?
Order of the mass of 4 children:
_____ , Noah, _____ , Lily (Heaviest)

Total mass of Harper and Mason 
= 2 x 37
= 74 kg

For Harper and Mason,
Mass of the lighter one = 1 u
Mass of the heavier one = 1 u + 2

Total mass of Harper and Mason
= 1 u + 1 u + 2
= 2 u + 2

2 u + 2 = 74 
2 u = 74 - 2
2 u = 72

1 u = 72 ÷ 2 = 36

The mass of the four children in consecutive order is 36, 37, 38 and 39.

Total mass of Harper, Lily and Mason
= 36 + 38 + 39
= 113

Answer(s): 113 kg