Question 691968
Originally there is {{{ .6*50 = 30 }}} gallons
of butterfat in the barrel.
Let {{{x }}} = gallons of skim milk to be added
{{{ 30 / ( 50 + x ) = .3 }}}
{{{ 30 = .3*( 50 + x ) }}}
{{{ 30 = 15 + .3x }}}
{{{ .3x = 15 }}}
{{{ x = 50 }}}
50 gallons of skim milk must be added
( another 50 gallons barrel is needed, too )
check:
{{{ 30 / ( 50 + x ) = .3 }}}
{{{ 30 / ( 50 + 50 ) = .3 }}}
{{{ 30 = .3*100 }}}
{{{ 30 = 30 n}}}
OK