Four children made the following statements.
Lily : The average of Rebecca's mass and my mass is 32 kg.
Lucas : I am the heaviest.
Rebecca : David is 2 kg lighter than Lucas.
David : Our masses are in consecutive order.

What is the total mass of Lily, Lucas and Rebecca ?
Order of the mass of 4 children:
_____ , David, _____ , Lucas (Heaviest)

Total mass of Lily and Rebecca 
= 2 x 32
= 64 kg

For Lily and Rebecca,
Mass of the lighter one = 1 u
Mass of the heavier one = 1 u + 2

Total mass of Lily and Rebecca
= 1 u + 1 u + 2
= 2 u + 2

2 u + 2 = 64 
2 u = 64 - 2
2 u = 62

1 u = 62 ÷ 2 = 31

The mass of the four children in consecutive order is 31, 32, 33 and 34.

Total mass of Lily, Lucas and Rebecca
= 31 + 33 + 34
= 98

Answer(s): 98 kg