Answer
a) 36 meters
b) 52 meters
Work Step by Step
We use the information from the x and y components to find:
$-\mu F_n = ma_x$ and $F_n=mg$
We use substitution to find:
$-\mu mg = ma_x$
$-\mu g = a_x$
Thus, we find:
$\Delta x = \frac{v_0^2}{-2a_x} \\ \Delta x = \frac{v_0^2}{2\mu g} $
Plugging in the different values for the friction yields an answer of 36 meters for a) and 52 meters for b), which is a difference of 16 meters.