The complete question is:
how much does Karen have for food?
For this case, we have that the full amount of money is:
12/100 + 1/10 + 2/9 + x = 1
Where,
x: fraction of money for food
Clearing x we have:
x = 1 - (12/100 + 1/10 + 2/9)
Rewriting:
x = 251/450
Thus, the amount of money for food is:
450 * x = 450 * (251/450) = 251
Answer:
Karen has for food about:
$ 251