KCET 2021 Math Solved Paper

Given,
Total number of questions in part A=6
Total number of questions in part B=7
Pattern to choose 10 questions from 13 questions is
4 from part A and 6 from part B or
5 from part A and 5 from part B or
6 from part A and 4 from part B
∴ Total required number of ways
=(‌6C4×‌7C6)+(‌6C5×‌7C5)+(‌6C6×‌7C4)
=(15×7)+(6×21)+(1×39)
=105+126+35=266