Recent Question/Assignment

There is another class called TffEvent, it was working good but thr counter doesn't work so I edited after that I stuck in the @overriden display event and book event at TffExperienceEvent class. and They say must keep track of thr price the ticket holders paid so they ask for recall, join two strings using concatenation but doesn't work with me
please I just tried everything if you can help me with that.

Looking for answers ?