EastCoastJ

i solved this a completely different way than the book (in a way that I think is easier to understand)
It says he made a deposit of $5,000 and then purchased $9000 worth of stock, so his margin is 5000/9000 = 0.5555
then i just did the simple margin call formula
30(10.5555) / (1.30) = 19.05
The 4000 is the difference between the amount of stock he purchased and the amount he actually deposited.