Sorry about the title, I'm not exactly sure what to call this type of problem.

It takes one man one day to dig a $2\text{ m} \times 2\text{ m} \times 2\text{ m}$ hole. How long does it take $3$ men working at the same rate to dig a $4\text{ m} \times 4\text{ m} \times 4\text{ m}$ hole?

I tried to solve using proportions, but it didn't work out. Can someone guide me in the right direction?

Sorry about the tag as well.