Roses can be purchased individually for $4.50, one dozen for $36, or two dozen for $50. What is the greatest number of roses that can be purchased for $680?  Choose the most appropriate option: A) 156 B) 162 C) 318 D) 324 E) 325

Rationale: buy as many $ 50 deals as possible . we can by 650 / 50 = 13 two dozen roses , thus total of 13 * 24 = 312 roses . we are left with 680 - 650 = $ 30 . we can buy 30 / 4.5 = ~ 6 roses for that amount . total = 312 + 6 = 318 . answer : c .
Answer: C