Question

how many ounces of a 40% alcohol solution should be mixed with 54 oz of a 70 % alcohol solution to produce a 60 % alcohol solution ???

Answer 1

let x ounces of 40% solution be added.
\[then \frac{ 40x }{100 }+\frac{ 54\times70 }{ 100 }=\frac{ \left( 54+x \right)\times60 }{100 }\]
\[40x+\left( 54\times70 \right)=\left( 54+x \right)\times60\]
\[4x+\left( 54\times7 \right)=\left( 54+x \right)\times6\]
\[4x+378=324+6x\]
6x-4x=378-324
2 x=54
x=54/2=27 ounces