You could just do process of elimination. So for the first one if you add them all up you would get 3,452 which is not correct, for the second one would not be correct since after you do 3 times 104 you can see it is wrong, for c it is also wrong since there is a 30 not a 30,000, for d it is correct since if you write it out is is 30,452, for E it is not correct just by looking at the problem, and for F it cannot be correct since it does not be the right answer
Tiger consumes 18lb/day of food. If we want to calculate how much is consumed in 28 days, assuming that rate is consistent, the answer is 18*28 = 504lb of food.