Assume that an investor buys one March NYSE Composite Index futures contract on February 1 at 67.5. The position is closed out after five days. The prices on the four days after purchase were 67.8, 68.1, 68, and 68.5. The initial margin is $3,500.

a. Calculate the current equity on each of the next four days.

b. Calculate the excess equity for these four days.

c. Calculate the final gain or loss for the week.

d. Recalculate (a), (b), and (c) assuming that the investor had been short over this same period.