y + 35 = ( y ) + ( y - 31 )
y + 35 = 2y - 31
Add both sides 31
y + 35 + 31 = 2y - 31 + 31
y + 66 = 2y
Subtract both sides y
y - y + 66 = 2y - y
y = 66
C i believe because they both can break it up those ways even if they might not be the most effective
The area of a circle:

r - the radius, which is equal to half the diameter d
The first circle:

The second circle:
the second circle has a diameter that is four times the diameter of the first circle.

The ratio of the area of the smaller cirlce to the area of the larger circle:

The ratio is 1:16.