To solve this problem using the alligation method, follow these steps:
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Identify the concentrations of the solutions:
- Higher concentration: 7%
- Desired concentration: 5%
- Lower concentration: 2%
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Set up the alligation:
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Subtract the desired concentration from the higher concentration: \[ 7% - 5% = 2% \]
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Subtract the lower concentration from the desired concentration: \[ 5% - 2% = 3% \]
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Place the results in ratio form:
The ratio of the two parts is given by the results from the above steps: \[ \text{Ratio} = \frac{3}{2} \]
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Expressing it in x:y format:
The ratio of the 7% solution to the 2% solution will be: \[ 3 : 2 \]
Thus, you should mix the 7% solution and the 2% solution in the ratio of 3:2 to obtain a 5% solution.