(2/5) of (2/3) of students = 4/15 of students study French. Then 1-(4/15) = 11/15 of students do not study French. The ratio you want is (4/15):(11/15) = 4:11
Solve for x by cross multiplying then isolating the variable: cross multiply 15x=90 Isolate the variable x=6 Solve for y by cross multiplying then isolating the variable: cross multiply 9y=90 Isolate the variable y=10