Since the amount of mush eaten per pig per day is assumed to be constant then
Using this info:
Solve for n. I get 4 days which is around what we'd expect from intuition (not like 0.4, 40 and 25 which I got when trying to solve!)
First, you need to know how much a pig will eat each day.
If 500 lbs feeds 20 pigs for 7 days, then if we set up the ratio mush : day
So 20 pigs will eat lbs of mush per day.
Now we can set up another ratio of mush : pigs
So 14 pigs will eat 50 lbs of mush per day.
Finally, setting up the ratio mush : days
So 14 pigs will eat 200 lbs of mush in 4 days.
This is a tough question for the SAT. I would do it with a ratio (direct proportion) followed by an inverse proportion as follows:
First I'll answer this question: "If 500 pounds of mush will feed 20 pigs for a week, then 200 pounds of mush will feed how many pigs for a week?"
Now I'll answer this question: "If you can feed 8 pigs for 7 days, then for how many days can you feed 14 pigs?"
The problem is particularly confusing because there are three active variables here. I don't believe I've ever seen this in an actual SAT problem (if it ever did occur you could probably get it wrong and still get an 800). I have seen an additional inactive variable by which I mean the third variable wasn't needed to solve the problem (it was just there to confuse you). I'm curious what book this problem came from.