A collection of books went on sale, and 2/3 of them were sold for $2.00 each. If none of the 36 remaining books were sold, what was the total amount received for the books that were sold?  Choose one.
A) $ 144 B) $ 135 C) $ 90 D) $ 60 E) $ 54

Rationale: since 2 / 3 of the books in the collection were sold , 1 / 3 were not sold . the 36 unsold books represent 1 / 3 of the total number of books in the collection , and 2 / 3 of the total number of books equals 2 ( 36 ) or 72 . the total proceeds of the sale was 72 ( $ 2.00 ) or $ 144 . the best answer is therefore a . answer : a .
Answer: A