Answer: 6:5
Explanation:
Let each little rectangle have the dimensions a by b (where a is the length and longer than b, the width). We find that l=3a because there are 3 lengths of a along l at the top of the crate and that l=4b because there are 4 lengths of b along l at the bottom of the crate. In addition, w=2b+a because there are 2 lengths of b and one length of a along w. Therefore, we can find b and a in terms of l and plug them into w=2b+a to find w in terms of l:
l=4b
b=l/4
l=3a
a=l/3
w=2b+a
w=2(l/4)+(l/3)
w=l/2+l/3
w=5l/6
If w=5l/6, l:w=l/(5l/6)=l(6/5l)=6/5
The correct answer is 6:5.