The!average!daily!metabolic!rate!for!elk!in$!$captivity!can!be$!$expressed!by$!$the!function!! r $=140\mathrm{.}2$m $0\mathrm{.}75!!$where!m$!$is$!$the!mass!!$($in$!$kg$)!$and!r$!$is$!$the!metabolic!rate!$($in$!$kcal$/$day$).!!$If$!$a$!2502$kg$!$elk!is$!$gaining!mass!at$!$a$!$rate!of$!2$kg$/$day$,!$how!fast!is$!$its!metabolic!rate!changing?!