Answer :
21 students divided by 3 groups = 7 students per group
7 students times 6 minutes each = 42 minutes per group
42 minutes per group times 3 groups = 126 minutes
The answer is 126 minutes
7 students times 6 minutes each = 42 minutes per group
42 minutes per group times 3 groups = 126 minutes
The answer is 126 minutes