Answer:
C=30
Step-by-step explanation:
Supposing that we have the lines
x+2=10y
and
3x+6=Yc.
Note that dividing by 3 the second line can be rewritten as
x + 2= Y c/3.
Remember that a line is written as
, in our case, both lines have
and
. Therefore, in orther that the two lines are equal, we need that
, hence 
Y=31.2
X=15.6
I rounded both to the nearest tenth place.