Acertain drug is made from only two ingredients: compound a and compound b. there are 8 milliliters of compound a used for every 5 milliliters of compound b. if a chemist wants to make 845 milliliters of the drug, how many milliliters of compound b are needed?

Let 8 milliliters of compound A and 5 milliliters of compound B be a mixture.

We can then find how many mixture is needed for 845 milliliters of the drug by dividing it by (8+5=13):

845 ÷ 13

=65

As 65 mixture is used and each mixture include 5 milliliters of compound B, we can find the amount of compound B by multiplying 65 by 5

65 x 5

=325 milliliters

Therefore the answer is 325 milliliters.

Hope it helps!