I cant solve this

Question

You need a 10% alcohol solution. On hand, you have a 40 mL of a 95% alcohol mixture. How much pure water will you need to add to obtain the desired solution?

Answer 1

If you have 40ml of 95% alcohol solution, that's 2ml of water and 38ml of pure alcohol.

If you just add water, then the amount of alcohol remains the same. To have a 10% solution, the amount of water needs to be 9X the amount of alcohol. So the total water will be 38 * 9 = 342ml. That means you have to add 340ml of water.

Check: After adding the water, the total volume will be 40 + 340 = 380ml. With 38ml pure alcohol, you have a 10% solution (38/380)

Answer 2

(95x+y)/(x+y)=10x

x=1

y=9.43