Sports Inn Bowling Lanes has set a pricing objective to maintain a markup of $$10\mathrm{.}50$ on lane rentals. The cost of providing the rental is $$4\mathrm{.}00.$ Every day, $($Early$)$ bowlers before $5$ p$.$m$.$ pay half$-$full price while $($twilight$)$ bowlers after $5$ p$.$m$.$ pay full$-$ price equaling $$15\mathrm{.}00.$ Typically, $75\%$ of the bowlers are $$twilight$$ bowlers.

i$.$ What regular price and sale price should Sports Inn set to meet its pricing objective?