You need 300 ml of a 65% alcohol solution. on hand, you have a 50% alcohol mixture. how much of the 50% alcohol mixture and pure alcohol will you need to obtain the desired solution?
you will need
ml of the 50% solution
and
ml of pure alcohol.

You will need  220 mL of the 60% solution  and  80 mL of pure alcohol.

Step-by-step explanation:

Let 'x' be the amount of 50% alcohol solution and y the amount of pure alcohol.

Therefore:  

(0.5x + y)/300 = 0.65 ⇒ 0.5x + y = 190

x + y = 300

Solving the sistem of equations:

x = 220 and y = 080

Therefore, You will need

220 mL of the 60% solution

and  80 mL of pure alcohol.

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