Question 1006734
Let {{{ x }}} = liters of pure alcohol to be added
{{{ .84*7 = 5.88 }}} liters of alcohol in 84% solution
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{{{ ( x + 5.88 )/ ( x + 7 ) = .93 }}}
{{{ x + 5.88 = .93*( x + 7 ) }}}
{{{ x + 5.88 = .93x + 6.51 }}}
{{{ .07x = .63 }}}
{{{ x = 9 }}}
9 liters of alcohol must be added
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check:
{{{ ( x + 5.88 )/ ( x + 7 ) = .93 }}}
{{{ ( 9 + 5.88 )/ ( 9 + 7 ) = .93 }}}
{{{ 14.88 / 16 = .93 }}}
{{{ 14.88 = 14.88 }}}
OK