13. (7 points) 8 years ago, the sum of the father and son's ages was 80 years old, this year the father's age is 3 times the son's age, how old is the son this year?
【Answer】Solution: Since the age 8 years ago is 8 years younger than this year's age, the total reduction in age for both father and son is: $8 \times 2=16$ (years).
The sum of their ages this year is: $80+16=96$.
$$
96 \div(1+3)=24 \text { (years) }
$$

Answer: This year, the son is 24 years old.