Alligation math


I understand how you arrived at the answers for your example and the first listed question example. However, when you did the second listed question example, it seemed to be done differently.

I worked the question like listed in the first two examples and was completely off in the answer. I understand how you arrived at the answer for this one also, and it seems easier.

Is there a way to determine which way I should use if there are different or better ways, or am I just way too confused for my own good?

Reply (by Keith): The basic framework for doing an Alligation is the same, which is using the tic-tac-toe grid to determine how many Parts of each concentration you will need.

After that, the problem takes a bit of a turn into a proportion math problem. This is where I believe you are getting confused. Here's the thing, you can use several different methods to finish the problem. Different people prefer different methods.

Let's say that you did your tic-tac-toe and found out that you need 1 part of solution x and 3 parts solution y. So, that's 4 parts needed. Now lets say we need a final solution of 2 Liters.

One way to do it is to divide 2000ml by 4, which would tell you how much each Part will be, then add it all up.

Another way to do it is to use proportions math.

Another way to do it is to take 3 parts divided by 4 parts which equals .75 or 75%. Then you Multiply .75 by 2000 = 1500ml of solution y.

As you can see,
once you get your Parts by Alligation then you make the rest of the moves you like to use to determine the amount of each ingredient.

Comments for
Alligation math

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Jul 08, 2010
by: Anonymous

Could you please explain #4 on practice test 5? I thought I had this down pat, and now this one is confusing me.

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