SOLUTION: You need 240 mL of a 45% alcohol solution. On hand you have a 30 % alcohol mixture and a 70% alcohol mixture. How much of each mixture will you need to obtain the desired amount?

Question 906678: You need 240 mL of a 45% alcohol solution. On hand you have a 30 % alcohol mixture and a 70% alcohol mixture. How much of each mixture will you need to obtain the desired amount?
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
wt= mL dn=100 sn1= sn2=%
a+b=240,
0.3*a+0.7*b=0.45*240
a=240-b
0.3*(240-b)+0.7*b=108
72-0.3b+0.7*b=108
0.4*b=36
b=90
a=240-b
a=150 mL at 30%
b=90 mL at 70%
check
0.3*150+0.7*90=0.45*240
45+63=108
108=108
ok

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