The margin requirement on the S&P 500 futures contract is 16%, and the stock index is currently 1900. Each contract has a multiplier of $50 a. How much margin must be put up for each contract sold Maron $ 15200 b. ll the futures price falls by 2% to 1862, what will happen to the margin account of an investor who holds one contact input the amount as a positive value) Margo account decreases by c-1. What will be the investor's percentage return based on the amount put up as margin? (Negative value should be indicated by minus sign. Round your answer to 2 decimal places.)