Luke is three years older than Rachel who is three years older than Daniel if their ages add up to 51 how old is Luke

Question

 Lucas three years older than Rachel who is three years older than Daniel if their ages add up to 51 how old is Luke 

Answer 1

Daniel: D

Rachel: D+3

Luke: D+3+3

D+D+3+D+3+3=51

3D+9=51

3D=51-9

3D=42

D=42/3

D=14

Luke: 14+3+3=20 years old