$$56\times5-45-55-50-60=70$$ kg 
There are $5$ people in Linda\textquotesingle s family with an average weight of $56$ kg. The weights of Linda, Linda\textquotesingle s mom, Linda\textquotesingle s sister, and Linda\textquotesingle s brother are $45$ kg, $55$ kg, $50$ kg, and $60$ kg, respectively. What is the weight of Harry\textquotesingle s dad? 
Options:
a) $$65$$ 
b) $$66$$ 
c) $$68$$ 
d) $$70$$ 
e) $$75$$ 