It's sounds a bit funny but the way to answer somebody like that is by saying Ramadan kareem back to them, the exact same way they greeted you, just like when saying salam alaikum, you can reply the exact same way
Muhammad 'Abd al-Karim has written: ''Ali Mubarak'
It means " may you have a generous , blessed Ramadan" , which is the month were Muslim people fast.
The last day of Ramadan is to be determined around sun set on the 29th of Ramadan. If the moon's crescent is sighted, then it's the end of Ramadan. If it's not seen, then fasting ends after fasting the 30th day. Contact your local Islamic center for your specific region.
Karim Ainouz's birth name is Karim Anouz.
Karim Prince's birth name is Karim A. Adesanya.
Karim Benbrik goes by Ben.
Karim Sheik's birth name is Karim Mamdouh Kamel.
Baker Karim's birth name is Abu-Baker Karim.
Karim Capuano's birth name is Antonio Karim Capuano.
Abdul Karim Laghari died in 2004.
Karim Mendiburu's birth name is Karim Mendiburu Contreras.
Karim Benzema is famous for being muslim and you can know he is muslim because of from where he comes from amd his name is a muslim name in fact