SOLUTION: a pharmacist wants to mix an ointment that is 20% zinc oxside with ointment that is 40% zinc oxide to make 60 grams of ointment that is 25% zinc oxide how many grams of each ointme

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: a pharmacist wants to mix an ointment that is 20% zinc oxside with ointment that is 40% zinc oxide to make 60 grams of ointment that is 25% zinc oxide how many grams of each ointme      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 702635: a pharmacist wants to mix an ointment that is 20% zinc oxside with ointment that is 40% zinc oxide to make 60 grams of ointment that is 25% zinc oxide how many grams of each ointment should t
he pharmacist mix together
Found 2 solutions by stanbon, josgarithmetic:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
a pharmacist wants to mix an ointment that is 20% zinc oxside with ointment that is 40% zinc oxide to make 60 grams of ointment that is 25% zinc oxide how many grams of each ointment should the pharmacist mix together
-------
Equation:
zinc + zinc = zinc
0.20x + 0.40(60-x) = 0.25*60
----
Multiply thru by 100 to get:
20x + 40*60 - 40x = 25*60
-20x = -15*60
x = (3/4)60
x = 45 grams (amt of 20% ointment needed)
60-x = 15 grams (amt of 40% ointment needed)
============================
Cheers,
Stan H.

Answer by josgarithmetic(39627) About Me  (Show Source):
You can put this solution on YOUR website!
Basic idea is (amount of zinc oxide) divided by (amount of mixture) equals fraction as zinc oxide.

%28quantity+zinc+oxide%29%2F%28quantity+of+mixture%29=fraction+zinc+oxide

Let x = grams of 20% to use, and let y = grams of 40% to use.

How much grams of zinc oxide?
0.20%2Ax%2B0.40%2Ay

How much mixture is needed? 60 grams needed, from the given description.
x%2By=60

What concentration zinc oxide is wanted? 25%, or 0.25.

We want this system...
%280.20%2Ax%2B0.40%2Ay%29%2F%2860%29=0.25
x%2By=60
Solve this system.