A certain drug is made from only two ingredients, there are five milliliters of part a and four milliliters of part b. If a chemist uses 353 milliliters of b, how many milliliters of the drug will be made?

You will have to divide 353 millimeters by 4:

353 : 4 = 88.25

now we have to multiply 88.25 by 9 (5+4), the total millimeters of only one portion of this drug

88.25 x 9 = 794.25

So he will make 794.25 millimeters of drug (that is if he has the part a too)

(If you should round 88.25 to 88, the answer would be 88 x 9 = 792)