Let x represent the amount that Fred gets for his allowance weekly.
Fred spent half his allowance on the movies. This means that the total amount that he spent on the movies is x/2. The amount that he is left with would be
x - x/2 = x/2
He washed the family car for six dollars. This means that the total amount that he is left with would be
(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
