Four children made the following statements.
Bryan : Rebecca is 2 kg heavier than Isaac.
Isaac : Our masses are in consecutive order.
David : The average of Bryan's mass and my mass is 50 kg.
Rebecca : I am the heaviest.

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

Total mass of David and Bryan
= 2 x 50
= 100 kg

For David and Bryan,
Mass of the lighter one = 1 u
Mass of the heavier one = 1 u + 2

Total mass of David and Bryan
= 1 u + 1 u + 2
= 2 u + 2

2 u + 2 = 100
2 u = 100 - 2
2 u = 98

1 u = 98 ÷ 2 = 49

The mass of the four children in consecutive order is 49, 50, 51 and 52.

Total mass of David, Rebecca and Bryan
= 49 + 51 + 52
= 152

Answer(s): 152 kg