Exams postponed

Zoya Khan (ABC) (800 Points)

24 April 2017  

 

Sorry for the misleading title,but this is urgent.

 

 

 

 

This is a RTP question. I want to know if there is any shhort way to decide how to appraoch in these type of questions. I mean I know how to solve them but has this to be hit and try everytime?