Three walls have wallpaper covering a combined area of 300 square meters. By overlapping the wallpaper to cover a wall with an area of 180 square meters, the area that is covered by exactly two layers of wallpaper is 40 square meters. What is the area that is covered with three layers of wallpaper?	Choose the correct choice from the following answers.
A) 5 square meters
B) 36 square meters
C) 40 square meters
D) 83.3 square meters
E) 120 square meters

Rationale: "300 - 180 = 120 sq m of the wallpaper overlaps ( in either two layers or three layers ) if 36 sq m has two layers , 120 - 40 = 80 sq m of the wallpaper overlaps in three layers . 80 sq m makes two extra layers hence the area over which it makes two extra layers is 40 sq m . answer ( c ) ."
Answer: C