Answer:
a. u = e^(0.25√0.25)
u = e^0.125
u = 1.13314845307
u = 1.1331485
The percentage up movement is 13.31%
b. d = 1/u
d = 1/ 1.1331
d = 0.88253464
d = 0.8825
The percentage downward movement = 1 - 0.8825 = 11.75%
c. Probability of upward movement(P) = (R - d) / ( u-d)
P = (1.04 - .8825) / ( 1.1331 - 0.8825)
P = 0.6285
P = 62.85%
d. Probability of a down movement in a risk-neutral world = 1 - P
= 1 - 0.6285
= 0.3715
= 37.15%