John spends $320 buying his favorite dolls. If he buys only small Monkey dolls, which are $4 cheaper than the large Monkey dolls, he could buy 40 more dolls than if he were to buy only large Monkey dolls. How much does a large Monkey doll cost?
Choose one:	A) $ 7.2	B) $ 7.5	C) $ 8	D) $ 9	E) $ 10

Rationale: a and b is not an integer . so we start with c if large doll costs $ 8 , then he can buy 320 / 8 = 40 large dolls and 320 / 4 = 80 small dolls . difference is 40 , which is we wanted . answer c .
Answer: C