Problem $6$: Determine the elevation of the lowest point of the curve

A $400$ ft equal tangent curve has its PVC at station $100+00$ and elevation $500$ ft$.$ The initial grade is $-4\mathrm{.}0\%$ and the final grade is $+2\mathrm{.}5\%.$ Determine the elevation of the lowest point of the curve.

Group of answer choices

$495\mathrm{.}08$ ft

$495\mathrm{.}25$ ft

$485\mathrm{.}23$ ft

$492\mathrm{.}04$ ft