Given as
The total number of students in XI = 20
The total number of students in XII = 20
The total number of students to be selected in a team = 11 (with atleast 5 from class XI and 5 from class XII)
The number of ways = (No. of ways of selecting 6 students from class XI and 5 students from class XII) + (No. of ways of selecting 5 students from class XI and 6 students from class XII)
= (20C6 × 20C5) + (20C5 × 20C6)
= 2 (20C6 × 20C5) ways