Question

How much water must be evaporated from a 70 oz, 15% saline solution to produce a 25% saline solution? Round your final answer to 1 decimal place if necessary.

Answer 1

28 oz of water

Explanation:

Percentage of salt in the original solution = 15%

Let the amount of water to be evaporated = w

If we remove w oz of water from 70 oz solution, the resulting solution contains:

`25\%\text{ of }(70-w)\text{ salt}`

So, we have the equation:

`0.15(70)=0.25(70-w)`

We then solve for w:

`\begin{gathered} 10.5=17.5-0.25w \\ \implies0.25w=17.5-10.5 \\ 0.25w=7 \\ Divide\text{ both sides by 0.25} \\ (0.25w)/(0.25)=(7)/(0.25) \\ w=28 \end{gathered}`

Thus, 28 oz of water must be evaporated from a 70 oz, 15% saline solution to produce a 25% saline solution.