52
- is prime? No
- is multiple of 3? No
continue
53
- is prime? Yes
continue
54
- is prime? No
- is multiple of 3? Yes
- is multiple of 4? No
continue
55
- is prime? No
- is multiple of 3? No
continue
56
- is prime? No
- is multiple of 3? No
continue
57
- is prime? No
- is multiple of 3? Yes
- is multiple of 4? No
continue
58
- is prime? No
- is multiple of 3? No
continue
59
- is prime? Yes
continue
60
- is prime? No
- is multiple of 3? Yes
- is multiple of 4? Yes
Therefore 60 is the answer, as it fits all the conditions
Simple trial and error.