Question 758500
Let {{{ x }}} = cups of 4% milk to be added
{{{ .01*8 = .08 }}} cups of butterfat in 1% milk
{{{ .04x }}} = cups of butterfat in 4% milk to be added
---------------------------------------------
{{{ ( .08 + .04x ) / ( 8 + x ) = .02 }}}
{{{ .08 + .04x = .02*( 8 + x ) }}}
{{{ .08 + .04x = .16 + .02x  }}}
{{{ .02x = .08 }}}
{{{ x = 4 }}}
4 cups of 4% milk need to be added
check:
{{{ ( .08 + .04x ) / ( 8 + x ) = .02 }}}
{{{ ( .08 + .04*4 ) / ( 8 + 4 ) = .02 }}}
{{{ .24 / 12 = .02 }}}
{{{ .24 = .24 }}}
OK