You purchase 100 shares of stock at $100 ($10,000); the margin requirement is 40 percent.

What are the dollar and percentage returns if

a) You sell the stock for $112 and buy the stock on margin?

b) You sell the stock for $90 and buy the stock on margin?

c) You sell the stock for $60 and buy the stock on margin?

(i need details how you solve it step by step i want understand this quastion)