There are total 12 questions. A candidate can choose 8 questions from 12 in the following pattern
1st
2nd
3rd
2
2
4
2
3
3
2
4
2
3
2
3
3
3
2
4
2
2
∴ Total number of ways =‌(‌4C2×‌4C2×‌4C4)+(‌4C2×‌4C3×‌4C3) ‌+(‌4C2×‌4C4×‌4C2)+(‌4C3×‌4C2×‌4C3)+ ‌(‌4C3×‌4C3×‌4C2)+(‌4C4×‌4C2×‌4C2)