V is a year older than S, S is two years older than M, R is a year older than…

Concept: When a puzzle gives only relative age differences (X is n years older or younger than Y) instead of absolute ages, express every person's age as an offset from one reference person's age. Comparing these offsets directly gives the correct age order, since a larger offset always means an older person.

Application:

1. Let M's age be the reference value, M.

2. R is a year older than M, so R = M + 1.

3. S is two years older than M, so S = M + 2.

4. V is a year older than S, so V = S + 1 = (M + 2) + 1 = M + 3.

5. Comparing the four offsets from M: M (+0) is less than R (+1), which is less than S (+2), which is less than V (+3).

Cross-check: Assign M a concrete value, say 20 years. Then R = 21, S = 22, and V = 23. The ordering 20 < 21 < 22 < 23 confirms the same result independently.

The smallest offset belongs to M, so M is the youngest of the four.