Question 954235
Let {{{ x }}} = ounces of pure acetone to be added
{{{ .19*( 27 - x ) }}} = ounces of acetone in 19% solution
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{{{ ( x + .19*( 27 - x ) ) / 27 = .37 }}}
{{{ x + .19*( 27 - x ) = .37*27 }}}
{{{ x + 5.13 - .19x = 9.99 }}}
{{{ .81x = 4.86 }}}
{{{ x = 6 }}}
6 ounces of pure acetone must be added
check:
{{{ ( x + .19*( 27 - x ) ) / 27 = .37 }}}
{{{ ( 6 + .19*( 27 - 6 ) ) / 27 = .37 }}}
{{{ ( 6 + .19*21 ) / 27 = .37 }}}
{{{ 6 + 3.99 = .37*27 }}}
{{{ 9.99 = 9.99 }}}
OK