You need a 40% alcohol solution...

Question

You need a 40% alcohol solution. On hand, you have a 550 mL of a 20% alcohol mixture. You also have 95% alcohol mixture. How much of the 95% mixture will you need to add to obtain the desired solution?

You will need

 ______ mL of the 95% solution

Answer 1

Let x be the amount of 95% mixture, then you have the following equation,

95% x + 20% 550 = 40%(x + 550),

Solve the equation, you'll get the answer.