"Señor, ¿cuántas maletas tiene usted?"
Translation:Sir, how many suitcases do you have?
In English it's much more natural to put 'Sir' at the end - a pity duolingo marks it as incorrect.
"Sir" is pretty often used as a way to get someone's attention. You were likely marked wrong because you changed the meaning of the sentence.
NO, it is 'Sir, how many bags have you?' No need for DO or GOT! It is getting annoying.
If you want another answer to be accepted, click the "report" button, and then click "my answer should be accepted".