I am not entirely sure what your asking but i think you mean which will coast the least and that would be 8 since it’s the smallest amount
Answer:
1.14 liters
Step-by-step explanation:
We have 8% glycerin solution and we need to make it 16% glycerin solution [more concentration].
When we add "x" liters, we add glycerin as well as changes the total. in 12 Liters, there is 12 * 0.08 = 0.96Liters of glycerin. How much we need to add to this??
Note, 16% = 0.16
We can write a Ratio as shown below, cross multiply and solve for x:

We need to add around 1.14 liters
Answer:
I think it is D. Because x=x and there's infinite possibilities.
5 kg is more precise because if you said 5212 g, they will be trying to see what the precise answer is so if you say 5 kg that will save all of the work.
P.S.: its not 5212 g, its 5000 g. :)
Im pretty sure that means what is y when x is -5. the answer is 5