here are two similar questionsThe question 2 was an example of the teacher's lecture. the question 18 is the homework. the solution of q2 is to use the margin call price which is initial price x (1- initial margin)/(1-maintenance margin). From my opinion, the Q18 should use the same equation but my answer is total different . The third picture is the analysis that given by the teacher. can you tell me why is that?

a) Total sales =25100=2,500 Margin Requirement =50% Initial Margin =50%2,500=1,250 b) Total Assets =2,500+1,250=3,750 Let Price be P Total share price =100P (3,750100P)/100P=0.30P=28.85 A margin call will be issued when the stock price reaches $28.85 or higher a) 25100=2500250050%=1250 $1250 should put into the account 2517%150%=17,86 2. You purchased 100 shares of ABC common stock on margin at $70 per share. Assume the initial margin is 50% and the minimum margin is 30%. Below what stock price level would you get a margin call? Assume the stock pays no dividend; ignore interest on margin. A. $21 B. $50 C. $49 D. $80 E. none of these 18. You are bearish on Canopy Growth stock and decide to sell short 100 shares at the current market price of \$25 per share. a. How much in cash or securities must you put into your brokerage account if the broker's initial margin requirement is 50% of the value of the short position? b. How high can the price of the stock go before you get a margin call if the minimum margin is 30% of the value of the short position