Question 953786
Find AMOUNTS of alcohol in each one 
of the mixes
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{{{ .3*.75 = .225 }}} liters
{{{ .4*.5 = .2 }}} liters
{{{ .9*.25 = .225 }}} liters
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{{{ .225 + .2 + .225 = .65 }}} liters of alcohol
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Add the liters of mixtures:
{{{ .75 + .5 + .25 = 1.5 }}} liters of mixture
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{{{ .65 / 1.5 = .43333 }}}
{{{ .43333*100 = 43.333 }}}
The alcohol percentage is:
43 and 1/3 %