1 Given that the ages of A, B, and C are all positive integers, A's age does not exceed twice B's age, B is 7 years younger than C, the sum of the three people's ages is a prime number less than 70, and the sum of the digits of this prime number is 13. Question: What is the maximum age of A?
1. Let Jia's age be $x$ years, and Yi's age be $y$ years, then Bing is $y+7$ years old, and $x \leqslant 2 y$.

Since the positive integers less than 70 and with a digit sum of 13 are only $49$, $58$, and $67$, the sum of the three people's ages (which is a prime number) can only be 67 years, i.e.,
$$x+y+(y+7)=67$$

This gives
$$x+2 y=60 .$$

Combining with
$$x \leqslant 2 y$$

We get
$$4 y \geqslant 60 \text{, i.e., } y \geqslant 15,$$

Thus,
$$x=60-2 y \leqslant 60-30=30,$$

Therefore, Jia is at most 30 years old (Note: Jia, Yi, and Bing being 30 years, 15 years, and 22 years old, respectively, meet the requirements).