(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
But i think I know what you need to do so first count the graph like see where it is pointed at then divide and u get ur answer Again im not sure but maybe