Question 1048300
Let {{{ x }}} = liters of the 20% solution needed
{{{ .2x }}} = liters of salt in the 20% solution
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{{{ ( .2x + .4*60 ) / ( x + 60 ) = .35 }}}
{{{ ( .2x + 24 ) / ( x + 60 ) = .35 }}}
{{{ .2x + 24 = .35*( x + 60 ) }}}
{{{ .2x + 24 = .35x + 21 }}}
{{{ .15x = 3 }}}
{{{ x = 20 }}}
20 liters of the 20% solution are needed
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check:
{{{ ( .2x + .4*60 ) / ( x + 60 ) = .35 }}}
{{{ ( .2*20 + .4*60 ) / ( 20 + 60 ) = .35 }}}
{{{ ( 4 + 24 ) / 80 = .35 }}}
{{{ 28 = .35*80 }}}
{{{ 28 = 28 }}}
OK