I need help with finding slope How can I find s in the equation? can you show the calculations to finding Slope for step by step $?$

The vehicle, which was traveling at a speed of $90k\frac{m}{h}$ in the downhill direction on a road, suddenly braked and stopped at $86\mathrm{.}25m.$ If the longitudinal friction coefficient of the road is $0\mathrm{.}40,$ what is the longitudinal slope of the road?

SOLUTION

Braking Distance $(BD)=0\mathrm{.}00394**\frac{V^2}{f+-s}$

$86\mathrm{.}25=0\mathrm{.}00394**\frac{{90}^2}{0\mathrm{.}4-s}$

$s=0\mathrm{.}03=3\%$