If 5% more is gained by selling an book for $ 350 than by selling it for $ 340, the cost of the book is:	Pick one.
A) 500	B) 400	C) 200	D) 300	E) 100

Rationale: "c 200 let c . p . be $ x . then , 5 % of x = 350 - 340 = 10 x / 20 = 10 = > x = 200"
Answer: C