Question 292424
How much does each oerson get? {{{30/18}}} so everyone gets one and 2/3 sausages

How many cuts? Trick question. Take 18 sausages out. You have 12 left.
Get a long knife. Line up the 12 sausages one next to the other, touching side to side. 
Make a cut that creates sausage pieces that are 2/3 and 1/3 in length. 
With the sausages lined up the correct way, ONE cut will let you create 12 2/3 sized pieces and 12 1/3 sized pieces.

That's a total of 24 pieces, plus the original 18 gives 42 total pieces.

I am sure the must be a formula, but given the way these sausages are given out, I don't see the need to use one.

One well placed cut does the trick.