In order to calculate the total amount of treat bags that Ms. Yung can make we would simply need to divide the weight of each bag's candy by the total weight of candy that Ms. Yung has. This would evenly divide the total amount of candy into as many bags as possible.
18.5 lbs. / 0.2lbs = 92.5 bags
Therefore, if we divide evenly Ms. Yung would be able to make a total of 92 treat bags because even though she has for half a bag left it would not be an entire treat bag like she wants.