Question 1080096
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I can solve it without using equations: Sharon must add 10 liters of water.


Then the total volume will be 5 + 10 = 15 and the soap concentration will be


{{{soap/15}}} = {{{(soap/5)*(1/3)}}} = {{{0.36*(1/3)}}} = 0.12 = 12%.   (Since {{{soap/5}}} = 0.36, according to the condition)
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