The two boxes shown are cuboids. 20 cm
4 cm
30 cm
3 cm
50 cm
10 cm
Work out how many of the smaller boxes you would need
to completely fill the larger one.

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.