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