Problema Solution

A pharmacist has a solution which is 20% alcohol and another solution which is 60% alcohol. She needs to make 10 liters of a 30% solution. How many liters of each solution does she need to use.

Answer provided by our tutors

to get 10 liters of a 30% solution, suppose u need x L 20% alcohol,and (10-x) L 60% alcohol, so

20%x+60%(10-x)=10*30%

6-0.4x=3

x=7.5 

so u need 7.5 liters 20% alcohol,and 2.5 liters 60% alcohol.

 

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