UPSC NDA Math Model Paper 1

Given: The question paper has two parts part 'A' and part 'B' such that each part has 10 questions.
Here, we have to find in how many ways a student can choose 8 questions from part 'A' and 5 questions from part 'B'.
The number of ways in which a student can choose 8 questions out of 10 questions in part ′A′=10C8
The number of ways in which a student can choose 5 questions out of 10 questions in part ′B′=10C5
So, the total no. of ways in which a student choose 8 questions from part 'A' and 5 questions from part ′B′=10C8×10C5