SOLUTION: A team composed of two grade11 and two grade 10 students is to be sent to a debate contest. If there are 60 grade 10 and 55 grade 11 students, in how many ways can the selection of

You can choose two 10-grades from 60 students by   =  = 1770 ways.


You can choose two 11-grades from 55 students by   =  = 1485 ways.


Finally, you have   = 1770*1485 = 2628450 ways to create your team of 4 students.