Question 559325
Let {{{x}}} = pounds of cashews needed
given:
{{{ x + 20 }}} = total pounds of mixture
{{{ 1.2/.25 = 4.8 }}} is cost/pound of cashews
{{{ 1.5/.25 = 6 }}} is cost/pound of Brazil nuts
{{{ 1.3/.25 = 5.2 }}} is cost/pound of mixture
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{{{ ( 4.8x + 6*20 ) / ( x + 20 ) = 5.2 }}}
{{{ 4.8x + 120 = 5.2*( x + 20 ) }}}
{{{ 4.8x + 120 = 5.2x + 104 }}}
{{{ .4x = 120 - 104 }}}
{{{ .4x = 16 }}}
{{{ x = 40 }}}
40 pounds of cashews are needed
check answer:
{{{ ( 4.8x + 6*20 ) / ( x + 20 ) = 5.2 }}}
{{{ ( 4.8*40 + 6*20 ) / ( 40 + 20 ) = 5.2 }}}
{{{ 192 +  120 = 5.2*60 }}}
{{{ 312 = 312 }}}
OK