Question 532246
Let {{{ x }}} = pounds of $8 coffee needed
given:
{{{ 60*15 = 900 }}} is cost of $15 coffee
{{{ 8x }}} = cost of $8 coffee
{{{ 60 + x }}} = total pounds of coffee in mixture
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{{{ ( 900 + 8x ) / ( 60 + x ) = 14 }}}
{{{ 900 + 8x = 14*( 60 + x ) }}}
{{{ 900 + 8x = 840 + 14x }}}
{{{ 6x = 900 - 840 }}}
{{{ 6x = 60 }}}
{{{ x = 10 }}}
10 pounds of $8 coffee are needed
check:
{{{ ( 900 + 8x ) / ( 60 + x ) = 14 }}}
{{{ ( 900 + 8*10 ) / ( 60 + 10 ) = 14 }}}
{{{ 980 / 70 = 14 }}}
{{{ 980 = 80 }}}
OK