i have two selectboxes

1 st selectbox = adultid

2 nd selectbox  = childid

if i select 1 in adultid , i want to show 2 options in childid

then when i select 2 in adultid , i want to show 4 options in childid

the above is simple and done..

then 

if i select  1 in childid , i show input box, then if 2 selected in childid, i show 1 more input box if 1st input box included already else show 2 input boxes ...

same for chilid selected 3 or 4..

but 

if i have childid  selected as 4  , then i select childid as 1  , i want to remove 3 input (make last 3  input box style display:none) 

pls advice how to do that in jquery