A merchant realizes a markup of​ $42 by selling an item at a markup of​ 37.5% of cost. The​ merchant's overhead expenses are​ 17.5% of the regular selling price. At a promotional​ sale, the item was reduced in price to​ $121.66.

​(a)What is the regular selling​ price?

​(b)What is the rate of markup based on the regular selling​ price?

​(c)What is the rate of​ markdown?

​(d) What is the profit or loss during the promotional​ sale?