Question 1105143
Let {{{ x }}} = quarts of pure ( 100% ) solution to be added
{{{ .05*3.5 = .175 }}} = quarts of pure ingredient in 5% solution
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{{{ ( .175 + x ) / ( 3.5 + x ) = .125 }}}
{{{ .175 + x = .125*( 3.5 + x ) }}}
{{{ .175 + x = .4375 + .125x }}}
{{{ .875x = .2625 }}}
{{{ x = .3 }}}
0.3 quarts of the pure ( 100% ) solution must be added
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check:
{{{ ( .175 + x ) / ( 3.5 + x ) = .125 }}}
{{{ ( .175 + .3 ) / ( 3.5 + .3 ) = .125 }}}
{{{ .475 / 3.8 = .125 }}}
{{{ .125 = .125 }}}
OK