$(170-168)-(168-160)-(168-162)+(175-168)=-5$.  $168+5=173$. 
There are $5$ people in Harry\textquotesingle s family with an average height of $168$ cm. The heights of Harry, Harry\textquotesingle s mom, Harry\textquotesingle s sister, and Harry\textquotesingle s brother are $170$ cm, $160$ cm, $162$ cm, and $175$ cm, respectively. What is the height of Harry\textquotesingle s dad? 
Options:
$$163$$ 
$$165$$ 
$$171$$ 
$$173$$ 
$$178$$ 