If a 19-cup mixture of powder and water contained 1 cup of powder. How many cups of powder must be added to get a mixture having powder and water in the ratio of 1:2?  Choose the correct answer
A) 6
B) 8
C) 17
D) 19
E) 24
Concentration of powder in Mix 1 = 1/19   Concentration of powder in Mix 2 = 1 ( i.e. 100% since it is all powder)   Concentration of powder in final mixture = 1/3   w1/w2 = (1 - 1/3)/(1/3 - 1/19) = 19/8   So for every 19 cups of mix1, you need to put 8 cups of powder to make the required mix with ratio 1:2.   ANSWER:19
<result>D</result>
If a 19-cup mixture of powder and water contained 1 cup of powder. How many cups of powder must be added to get a mixture having powder and water in the ratio of 1:2?