Translate into Hindi. Who are you? And who's this boy?

Translate into Hindi. Who are you? And who's this boy?

आप कौन हैं? और यह लड़का कौन है?

Thank you for your reply. You are right.
Who are you?  
आप कौन हैं?  or तुम कौन हो? Tum kaun ho?

आप कौन हैं?  and  तुम कौन हो?  Both are correct.  However,there is a small difference between आपको and तुमको , which is of mutual respect to each other.
आप (you) is address to someone old/older is age/more respected/more formal and तुम is for friends/juniors/same age.
 

Hi Sudhanshu,

Thank you for your comment.