The first thing you should know to solve this problem is the following conversion: 1 lb = 453.592 grams Therefore, we can make the following rule of three: 453.592 grams ------> 171 $ 15 grams --------------> x Clearing x we have: x = (15 / 453.592) * (171) x = $ 5,655 Answer: the cost of 15 grams is: x = $ 5,655
