A buyer plans to purchase 300 spring dresses to retail for $79.99. A 56% markup is needed on the total purchase. She makes an initial purchase of 140 at a cost of $37.50 each. What average unit cost is needed for the balance of the purchases to attain the planned markup percentage? What markup percentage was attained on the first purchase? What markup percentage does the buyer require on the balance of purchases to achieve the overall needed markup dollar plan?