To answer any ratio question like this, you add up the ratio values (so 4 + 3) and then divide the total number by that. In this case, 4 + 3 = 7, so 42 ÷ 7 = 6.
This means that 6 would be 1 in terms of the ratio, so we need to multiply it first by 4 to get Superman, which is 24, and then by 3 to get Spiderman, which is 18.
I hope this helps!