A sag vertical curve connects a $3\%$ grade with a $+2\mathrm{.}5\%$ grade on a rural arterial highway.

The grades intersect at station $(220+000$m$)$ at an elevation of $100$ m$.$ If the criterion selected for design

is the minimum stopping sight distance and the design speed of the highway is $80$ km$/$h$,$ compute:

$$ the station and elevation of the BVC and EVC

$$ the station and elevation of the low point of the curve

$$ the elevation of the curve at $25$m before station PVI