The sum of Ben\textquotesingle s age and Ben\textquotesingle s grandma\textquotesingle s age is $$96$$.  Since grandma is three times older than Ben, on the number line, $96$ can be divided into $$4$$ portions, and each portion is $$96\div(1+3)=24$$.  Ben is $$24$$ years old, and grandma is three times older.  $$24\times 3=72$$ 
The sum of Ben\textquotesingle s age and Ben\textquotesingle s grandma\textquotesingle s age is $$96$$. Ben\textquotesingle s grandma\textquotesingle s age is three times older than Ben\textquotesingle s age. How old is Ben\textquotesingle s grandma? 
Options:
a: $$24$$ 
b: $$48$$ 
c: $$72$$ 
d: $$96$$ 