Question 1124019
Let {{{ x }}} = pounds of $20 coffee needed
————————-
{{{ ( 20x + 60*90 ) / ( x + 90 ) = 50 }}}
{{{ 20x + 5400 = 50*( x + 90 ) }}}
{{{ 20x + 5400 = 50x + 4500 }}}
{{{ 30x = 900 }}}
{{{ x = 30 }}}
30 pounds of the $20/lb coffee are needed
———————-
Check:
{{{ ( 20*30 + 60*90 ) / ( 30 + 90 ) = 50 }}}
{{{ 6000 / 120 = 50 }}}
{{{ 50 = 50 }}}
OK