The answer would be C. When you isolate X you get 4/5 turn that into a decimal you have 0.8. Then you isolate Y you get 3/5 Turn that into a decimal and you get 0.6. Therefore the solution has 1 answer.
90/2 is 45.. 60/2 is 30.. 30+45=75... 75 students would be able to be in each of the 2 groups, each containing 45 girls and 30 boys ... Hope I helped (:
