A marketing firm determined that, of 200 households surveyed, 80 used neither Brand W nor Brand B soap, 60 used only Brand W soap, and for every household that used both brands of soap, 3 used only Brand B soap. How many of the 200 households surveyed used both brands of soap?
Select:
A) 15
B) 20
C) 30
D) 40
E) 45

Rationale: solution for soap w and soap b ( d ) 40
Answer: D