Answer:
8/8
Explanation:
16/40 as a fraction is 0.4, and it's the same for 2/5. When you're diving fractions you can se KCF, where you keep the first fraction, change the sign (in this case a division symbol) to multiplication, and then flip the fraction (if it was 2/3 then it would now be 3/2).
Regardless, when dividing 2 of the same numbers you'll always get one (disregarding 0) to my knowledge atleast, and 8/8 is the same as 1, 2/2, 3/3, 4/4, and so on, therefore, any of these can be your answer if it equates to one.