Question

A student is to answer 10 out of 13 questions in an examination such that he must choose atleast 4 from the first five questions. The number of choices available to him is

• A. 196
• B. 280
• C. 320
• D. 156

Answer 1

The correct option is A 196

4 from first 5 and 6 from rest \(= ^5C_4 \times ^8C_6 = 5 \times28 = 140\)
5 from first 5 and 5 from rest \(= ^5C_5\times ^8C_5 = 56\)
Total number of ways = 196