17. (3 points) Xiaopang and Xiaoya both have their birthdays in May, and both are on a Wednesday. Xiaopang's birthday is later, and it is known that the sum of their birthday dates is 38. Xiaopang's birthday is on May $\qquad$th.
17. (3 points) Xiaopang and Xiaoya both have their birthdays in May, and both are on a Wednesday. Xiaopang's birthday is later, and it is known that the sum of their birthdays is 38. Xiaopang's birthday is on May $\qquad$.

【Solution】Solution: $38=7+31=8+30=9+29=10+28=11+27=12+26=13+25=14+24=15+23=16+22$,

Since both of their birthdays are on a Wednesday, the difference in days between their birthdays must be a multiple of 7;
Upon inspection, only $26-12=14, 14$ is a multiple of 7,
That is, if Xiaoya's birthday is May 12, and Xiaopang's birthday is May 26, they differ by 14 days, which meets the conditions. Answer: Xiaopang's birthday is May 26.

Therefore, the answer is: 26.