For a certain state, the function $$f(x) = 0.4x^{2}-32x+830$$ models the number of accidents, $f(x)$, per 50 million miles driven as a function of a driver's age, $x$, in years, where $x$ includes drivers from ages 16 to 74, inclusive. The graph of $f$ is shown above. Use the equation for $f$ to solve:

a) Find the number of accidents per 50 million miles driven for drivers age 19.
Answer: accidents per 50 million miles

b) Find the number of accidents per 50 million miles driven for drivers age 55.
Answer: accidents per 50 million miles

c) For what value of $x$ does the graph have its lowest point? This is the age of drivers with the fewest accidents.
Answer: