The answer would be 11/60 or 0.183. All you do is subtract 7/12 - 2/5
Check the picture below.
now, if those two angles are corresponding, that means they're equal, therefore then
5x + 15 = 115
and surely you know what "x" is, and for that value, the angles are corresponding and therefore the lines are parallel.
It Equals 5.875 Hope this helps
For the value of n it would be 40