The son was born when his mother was 28 years old. The father is older to the mother by 4 years. If the current ages of the father and mother are in the ratio 9:8, what is the current age (in years) of the son?
You have the answer. Trap Analysis is why the other three were written.
Not a worked solution repeated four times — the specific reasoning error each wrong option was built to reward, and why this one tests execution slip.
See pricing50 are analysed free — try those first.