Question 1066351
The ratio of onions to grilled steak is
{{{ 1 / 6.6 }}} kg/kg
I can multiply top and bottom by the same number
and the ratio doesn't change
{{{ 10/66 }}}
{{{ 5 / 33 }}} 
---------------
Let {{{ x }}} = kg of onions to make tacos
{{{ 617.6 - x }}} = kg of grilled steak to make tacos
---------------
I can say:
{{{ 5 / 33 = x / ( 617.6 - x ) }}}
Multiply both sides by {{{ 33*( 617.6 - x ) }}}
{{{ 5*( 617.6 - x ) = 33x }}}
{{{ 3088 - 5x = 33x }}}
{{{ 38x = 3088 }}}
{{{ x = 81.3 }}}
and
{{{ 617.6 - 81.3 = 536.3 }}}
81.3 kg of onions to make tacos
536.3 kg of grilled steak to make tacos
---------------------------------------
check:
{{{ 81.3 / 536.3 = 5/33 }}}
{{{ .1516 = .1515 }}}
error due to rounding off, I think
OK