Alligation math is a little known shortcut used by pharmacy techs and pharmacy students. It's also known popularly in pharmacy tech school as tictactoe math.
Here's the next steps in how to work an alligation:
( Cont'd from previous page )
So, now the amounts of the differences you found become the "Parts" of the % directly across the grid from it.
→ Parts of the 3% → Parts of the 1% 

On your paper, write Parts of ___% Then, Add up the total "Parts" 
Now, take a look back at the question and look for the total volume needed.

On your paper, to the left of number of parts, write the needed volume Then, A division sign 
Do the Math: Now, you've divided the final solution volume into "Parts". In this case, there's 125mL per part. 

Now, go back up to the "parts" and write the volume per part. The Answer: The question asked how much 3% to use. So, that's :1 part X 125mL = 125mL of the 3% 
Now, go to:
Alligation Math II  additional explanation
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