Question

You need a 5% alcohol solution. On hand, you have a 60 mL of a 60% alcohol mixture. How much pure waterwill you need to add to obtain the desired solution?

Answer 1

It is given that a 5% alchohol solution needs to be prepared.

It is given that 60ml of 60% pure alchohol solution.

So let x ml of pure water be added, so it follows:

`60((60)/(100))+x((0)/(100))=(60+x)(5)/(100)`

Solve for x to get:

`\begin{gathered} 36=(\mleft(60+x\mright))/(20) \\ 720=60+x \\ x=660 \end{gathered}`

660 ml of pure water needs to be added to get the 5% solution.

b) You will need 660ml of pure water to obtain 720ml of the desired 5% solution.