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# How do you do three number ratios?

Wiki User

2013-07-10 23:37:29

Divide all 3 numbers by the smallest. If you end up with floating point numbers, you can either round them to the nearest whole or multiply out until you get to whole numbers and then divide the resultant numbers by a common foctor. i.e.

14:8:78

14 ÷ 8 = 1.75

8 ÷ 8 = 1

78 ÷ 8 = 9.75

So you have 1.75 : 1 : 9.75 which rounded gives 2:1:10

Multiply the numbers out to get integers gives 175:100:975

Divide by 5 = 35:20:195

Divide by 5 again = 7:4:39

If you round the original numbers to the nearest 5, you get 15:10:80

Divided by 5 = 3:2:16

If you carry out the division equation on that ratio;

3 ÷ 2 = 1.5

2 ÷2 = 1

16 ÷ 2 = 8

1.5 : 1 : 8 = approximately 2:1:10

There are loads of different ways to do ratios. I find using the division technique with a bit of rounding works the best.

So 14:8:78 = 2:1:10 = 7:4:39 = 3:2:16 approximately.

-NEW RESPONSE-

There appears to be a HUGE amount of rounding in there and I don't know why. To deal with 3 number ratios you need to figure out what the question is, if you are trying to figure out given 3 chemicals in a ratio how much you need of each given a specific amount of final substance? Or are you asking if you need 3 ingredients in a ratio, and you have a certain amount of 1 how much do you need of the others?

The first part is by adding all the numbers together, 14:8:78, gives us 100. Then taking the total amount you need at the end, divide by 100, then multiply by each of those numbers in the ratio to find out how much of that ingredient you need.

The second type, you just have to figure out what multiple you need of the original number in the ratio to get to the new amount you have. Example, if you have 20 ounces of the first chemical (14), to get 14 to 20, you just take 14 and multiply it by 20/14. Then you would multiply the 8 and 78 by 20/14 as well. That gives you the amount of each of the others you would need.

I am really not sure what the original poster of this response was talking about... DON'T ROUND LIKE THAT until the end of the problem.

Wiki User

2013-07-10 23:37:29
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