Question 864289
the first can be any of 7 students
the second any of 7 teachers
any of 6 students
any of 6 teachers
any of 5 students
any of 5 teachers
any of 4 students
any of 4 teachers
any of 3 students
any of 3 teachers
any of 2 students
any of 2 teachers
any of 1 students
any of 1 teachers
7*7*6*6*5*5*4*4*3*3*2*2*1*1=25,401,600
49*36*25*16*9*4=25,401,600