Question 534421
Let {{{x}}} = pounds of nuts needed
{{{ 8x }}} = cost of nuts in dollars 
given:
{{{ 3*70 = 210 }}} = cost of raisins in dollars
--------------
{{{ ( 8x + 210 ) / ( x + 70 ) = 6 }}}
{{{ 8x + 210 = 6*( x + 70 ) }}}
{{{ 8x + 210 = 6x + 420 }}}
{{{ 2x = 210 }}}
{{{ x = 105 }}}
105 pounds of nuts are needed
check:
{{{ ( 8*105 + 210 ) / ( 105 + 70 ) = 6 }}}
{{{ ( 840 + 210 ) / 175 = 6 }}}
{{{ 1050 / 175 = 6 }}}
{{{ 1050 = 1050 }}}
OK