Question 697324
Let {{{ x }}} = the number of marbles that
Donald gave Louie.
Louie hid {{{ (1/3)*x }}}, so there were 
{{{ (2/3)*x }}} marbles left.
Dewey hid 1/3 of the marbles left, so
that means there are {{{ (2/3)*(2/3)*x = (4/9)*x }}}
marbles left.
After Daisy took 2 marbles, there are
{{{ (4/9)*x - 2 }}} left
Huey saw 10 marbles in the pile
so, I can say
{{{ (4/9)*x - 2 = 10 }}}
{{{ 4x - 18 = 90 }}}
{{{ 4x = 108 }}}
{{{ x = 27 }}}
Donald gave Louie 27 marbles
check:
Louie hid 1/3, or 9 marbles, so
there are 18 left
Dewey hid 1/3 of these, or {{{ 18/3 = 6 }}}
so, there are 12 left
Daisy took 2, so there are
10 left
That's what Huey saw
OK