Ann sleeps just $$8$$ hrs. each day, so in $$10$$ days, she\textquotesingle s \emph{awake~}~\uline{~~~~~~~~~~}~hrs. 
Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations
Ann\textquotesingle s awake $$16$$ hours each day. In $$10$$ days, that\textquotesingle s $$(10\times 16)$$ hours. 