When does a joint sub-committee work on a bill? º The bill has to do with federal spending

º There are no current committees that deal with the particular subject

º Both the House and Senate are working on similar bills that need to be combined

º The bill has to do with the legalization of marijuana

Both the House and Senate are working on similar bills that need to be combined

Explanation:

A joint sub-committee work on a bill in which "both the House and Senate are working on similar bills that need to be combined."

This is because a joint sub-committee is a committee that has members from both the Houe and Senate. They then work together on a particular subject or bills such that the outcome is combined in making a shared function.