Have you got an answer?

Have you got an answer ?

 

Three men went to a hotel  to share a room.   The clerk asked for $300.   Each man paid $100,  making up the $300.   The hotelkeeper then decided to allow a discount for the day, charging only $250 for the room.   He told the clerk to return $50 to the three men.   The clerk pocketed $20 for himself.  He gave the remaining $30 back to the three men.   Each man took back $10.    Therefore, each man paid 100 - 10 = $90  to  the hotel.   $90 x 3 = $270 + the clerk's $20 =  $290.   Question:  Where has the remaining $10 gone?   There is widespread interest in this question posted by a university in N.Z. Many people are still trying to work out an answer.

 

 

 Anyone can give me an answer...?