Question 720619
Let {{{ w }}} = liters of water to be added
{{{ .4*8 = 3.2 }}} liters of salt in 40% solution
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{{{ 3.2 / ( 8 + w ) = .1 }}}
{{{ 3.2 = .1*( 8 + w ) }}}
{{{ 3.2 = .8 + .1w }}}
{{{ .1w = 2.4 }}}
{{{ w = 24 }}}
24 liters of water must be added
check:
{{{ 3.2 / ( 8 + 24 ) = .1 }}}
{{{ 3.2 / 32 = .1 }}}
{{{ 3.2 = 3.2 }}}
OK