Alligation Math
Q. A script calls for 25 grams of Hydrocortisone cream 15%. Your Pharmacy stocks both 5% and 20% formulations. How much of the 20% will you use in this order ? (Attn: In the video I round numbers to the nearest quarter Gram.) Here's another way to do it.Q. A script calls for 25 grams of Hydrocortisone cream 15%. Your Pharmacy stocks both 5% and 20% formulations. How much of the 20% will you use in this order ? Since you have one stronger formula and one weaker formula you can properly combine them to make your desired formula using Alligation Math. Based on the above factors, you have three numbers to work with. The best way to get started is to draw out a "tic-tac-toe". 1) Then, take the two formulas you have and place them in the top left and bottom left positions and your desired formula in the center of the Tic Tac Toe.
2) Now, do two diagonal subtractions to get the difference between what you have and what you want and write the answers in the right hand top and bottom. You will have one negative number, but always write it as positive.
3) What you have done is determine how many parts of each formula to use to arrive at the desired formula.
4) Now you know that you need 15 total parts.
5) Take the number of Parts for the first formula (the 20%) and divide it by the Total number of parts. 10 (parts) ÷ 15 (Total Parts) = .67 6)Then, take the amount of grams you need and multiply it by that. 25 Grams X .67 = 16.75 grams of the 20% 7)Then, To figure out the rest of the solution, Simply make up the difference with the 5% 25.00 Total grams - 16.75 grams of the 20% 25.00 - 16.75 = 8.25 8.25 Grams of the 5% FINAL ANSWER
The answer to the question: = 16.75 grams of the 20% Want another Alligation step-by-step example ? An Alligation Math question was posted by a visitor and answered on this next page. Where would you like to go now? More Alligation Math Back to Math Home Page Back to homepage Site Map |
