Question 608055
Hope this is impressive
Let {{{ x }}} = cups of grapefruit juice that needs to be added
{{{ .1*20 = 2 }}} = cups of grapefruit juice in 20 cups of 10% punch
( the part that isn't grapefruit juice might be water, but that
doesn't really matter )
----------------
{{{ ( x + 2 ) / ( x + 20 ) = .25 }}}
{{{ x + 2 = .25*( x + 20 ) }}}
{{{ x + 2 = .25x + 5 }}}
{{{ .75x = 3 }}}
{{{ x = 4 }}}
You must add 4 cups of grapefruit juice
check:
{{{ ( 4 + 2 ) / ( 4 + 20 ) = .25 }}}
{{{ 6/24 = .25 }}}
{{{ 6 = .25*24 }}}
{{{ 6 = 6 }}}
OK