There are two possibilities each day (contestant wins or contestant loses).
2^5 = 32 outcomes
But we only want the outcomes where two of the contestants are winners. From the 5 days, pick 2 that will be the winning days.
C(5,2) = (5 * 4) / (2 * 1) = 10 ways
So the probability is 10/32 = 5/16
5/16 = 0.3125 = 31.25%
Answer: 31.25%