Pharmacy Dilution MathClick here to see the Proper Algebra Method The pharmacist hands you a 1.5L bottle of a 20% solution and asks that you mix it with sterile water to make as much 12% solution as possible. How much sterile water will you use ? A. 525mL B. 800mL C. 1000mL D. 1250mL In this video is how to do it using proportions math. alligation, and basic algebra. Another way to do this problem is to use the formula:C1 X V1 = C2 X V2 C1= Concentration 1 V1= Volume 1 C2= Concentration 2 V2= Volume 2 1) First, plug it all in: (.20)(1500ml) = (.12)( X )(Volume 2 is unknown or "X")↓ ↓ ↓ 2) Do the multiplication 300ml = .12X ↓ ↓ ↓ 3) Do the division to isolate X ↓ ↓ ↓ 4) Now you have the larger volume. (but, this is not the final answer) 2500mL = X ↓ ↓ ↓ 5) Figure out the difference between the Smaller and larger volumes. (this is the final answer) 2500mL - 1500mL -------- 1000mL - would be added to the solution. The answer is C. If you want to cross check your answer, you could by taking this new information and doing an Alligation. This type of pharmacy tech math may be more difficult for those who have not taken algebra in school or pharmacy dilution math before. Want to see the proper algebra way
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1) The Equation Set-up:
1500(.20) + X (0.00) = (1500 + X).12
2) Do the math:
1500(.20) + X (0.00) = (1500 + X).12
300 = 180 + .12X
120 = .12X
3) Isolate for "X":
| = | ||
4) Solution:
1000 = X
You would need to add 1000ml of sterile water.
Answer = "C"
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