Nice approach sanyu4. I used other one. We have 79 registrations vs 59 students we know that we have 6 students in two groups. Therfore, we have: 77 - (6*2) = 65 reg. and 59 - 6 = 53 stud. We have 65 reg. vs. 53 stud. We need to get eventually the equal numbers so we need to eliminate the three grou...