3/8! This is because if he were to have 3 blue and 5 red and added them you’d get 8, in which that’s the denominator, your numerator will be the amount of blue marbles making the answer 3/8
I dont know how to solve it but since the answer shows as 6 and -7, if you plug it in as x values, one tiem as 6 and second time as -7 it doesnt equal 42
