Recently i became US Citizen. how long it will take if I sponsor my 24 year old brother back home to get his green card??

thanks everyone.

Brothers and Sisters of USC fall under Family Category 4 and there is really very long wait for them. It will take between 14 - 18 years for your brother to come here.
It will be little faster, if you sponsor your parents and they will be here in a year. Then when they will be citizen then they can apply for him, still this whole process will take about 8 - 10 years.
Other option is to bring him on Student Visa or employment Visa, if he can qualify. Once he is here then he can get several chances to get legalization.
Good luck.

OK,

But a parent filing for a married child, how long does that take for Green Card?

To Longing:
If a USC parents sponsors a married son/daughter, it usually takes about 3 - 6 depending on a country of residence.
Good luck.