Verified Answer :

Mean = (Sum of values)/(Number of values)

\(Mean\\ \\ =\frac { 55+62+61+54+68+72+59+61+70 }{ 9 } \\ \\ =\frac { 562 }{ 9 } \\ \\ =62.4\quad mph\quad (1\quad d.p)\\ \\\)

Range = Highest Value - Lowest Value

\(Range\\ \\ =72-54\\ \\ =18\\ \\\)