Question 237385
You got it right.
{{{P1/T1=P2/T2}}}
Since you're looking for P1 in this problem, you need to multiply T1 on both sides.  Which gives you:
{{{P1=P2*T1/T2}}}
Now substitute values:
{{{P1=6.8mm*33K/27K}}}
The unit of measure K (Kelvin Degrees) cancels, so you're left with mm.
{{{P1=8.31mm}}}