amy is x years old her brother (bobby)is 9 times older than amy ,their mother is 3 times as old as amy ,their father is twice as d as bobby

Answer 1

amy's age ---- x
brother's age = 9x
mother's age = 3x
father's age = 2(9x) = 18x

ridiculous data:
e.g. let x = 5
then amy is 5
brother is 45
mother is 15
father is 80

Of course it would help if you used proper punctuation and grammar, and proof-read your post.