Given the following information,

The margin requirement=50%.

The margin call ratio = 30%.

Stock price: $ 60

Interest rate on margin borrowing (call rate): 5%

Expected dividend: $2

Holding period: 1 year

Please estimate a) the margin trading return if the stock price increases to $80

b) the margin trading return if the stock price decreases to $45

c) the price which triggers the margin call.

d) If the margin-call triggering price is $25, please estimate the margin requirement, given everything else equal.