An alchemist discovered that the formula expressing the correct proportions needed to turn ordinary metal into gold is G = 3/2M + 15, where G is the number of gold bars and M is the number of metal bars. If a metal bar weighs twice as much as a gold bar, how many metal bars will yield an equal weight of gold?	Pick one
A) 10
B) 15
C) 22.5
D) 30
E) 67.5
Plug in the answer choices!   A --- 30/2 + 15 = 30 --- wrong   B --- 45/2 + 15 = not an integer --- wrong   C --- 22.5(3/2) + 15 = not an integer --- wrong   30 --- 90/2+15 = 60 --- CORRECT   ANSWER:30
<result>D</result>
An alchemist discovered that the formula expressing the correct proportions needed to turn ordinary metal into gold is G = 3/2M + 15, where G is the number of gold bars and M is the number of metal bars. If a metal bar weighs twice as much as a gold bar, how many metal bars will yield an equal weight of gold?