Question 750955
Let {{{ x }}} = cc's of 13% solution to be added
{{{ .13x }}} = cc's of salt in 13% solution
{{{ .23*80 = 18.4 }}} cc's of salt in 23% solution
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{{{ ( .13x + 18.4 ) / ( x + 80 ) = .17 }}}
{{{ .13x + 18.4 = .17*( x + 80 ) }}}
{{{ .13x + 18.4 = .17x + 13.6 }}}
{{{ .04x = 4.8 }}}
{{{ x = 120 }}}
120 cc's of 13% solution need to be added
check:
{{{ ( .13x + 18.4 ) / ( x + 80 ) = .17 }}}
{{{ ( .13*120 + 18.4 ) / ( 120 + 80 ) = .17 }}}
{{{ ( 15.6 + 18.4 ) / 200 = .17 }}}
{{{ 34 = .17*200 }}}
{{{ 34 = 34 }}} 
OK