Self-study
The increase in the price of jet fuel is due to a sharp decrease over the past year in the supply of jet fuel available relative to demand. ████████████ ███ ██████ ██ ███ ████ █████████ ███ ████ ██ ██████ █████ ████ ██ ███ ████ █████
Stimulus Summary: Surprising Phenomenon
The stimulus tells us that the price of jet fuel has increased because the supply has decreased "sharply" relative to demand. But the amount of jet fuel available for sale is larger today than it was last year.
Analysis: Notable Inferences
Even though this is a Must Be True question, the stimulus is similar to what we might expect for a Resolve, Reconcile, Explain question: two statements that seem on the surface to be in tension with each other. So start by thinking of this as an RRE question, and realize that there's no contradiction in the stimulus. We're dealing with a relative decrease. A decrease in the size of the jet fuel supply relative to demand doesn't rule out an actual or absolute increase in the size of the jet fuel supply. It could just be that demand has increased even more dramatically. In fact, since we know that the supply of jet fuel on the market has in fact increased over the last year, the demand for jet fuel must have increased even faster within the last year for the supply of jet fuel to have decreased relative to demand.
10.
If the statements above are █████ █████ ███ ██ ███ █████████ ███████████ ███ ██ ████████ █████ ██ ███ █████ ██ █████
a
The demand for ███ ████ ███ █████████ ████ ███ ████ █████
Correct. If the supply of jet fuel available for sale has increased (which it has), and the supply of jet fuel has still decreased relative to demand (which it has), then it has to be true that demand has also increased — and has increased more than supply.
b
The fuel efficiency ██ ███ ███████ ███ █████████ ████ ███ ████ █████
Incorrect. The stimulus doesn't say anything about jet engines' efficiency. This could be true, though it would be surprising if it were — you would expect more efficient engines to mean less demand for fuel, and we know that demand for jet fuel must have increased. But we can't conclude that (B) must be true just from looking at the stimulus.
c
The number of ███ ███████ ███████ ███ █████████ ████ ███ ████ █████
Incorrect. The stimulus doesn't give us any information about how changes in supply and demand for jet fuel relate to the number of jet flights. Like (B), this answer choice could be true, though it would be surprising if it were — you would expect fewer flights to mean less demand for fuel, and we know the demand for fuel must have increased in the last year. But we certainly can't conclude that (C) must be true from the stimulus.
d
The cost of ████████ █████████ ███ ███ ████ ███ █████████ ████ ███ ████ █████
Incorrect. It's not clear how the cost of refining petroleum into jet fuel affects the supply and demand for the finished product. Just from looking at the stimulus, we can't say (D) must be true.
e
The supply of █████████ █████████ ███ ███ ████ ███ █████████ ████ ███ ████ █████
Incorrect. We're not interested in the supply of petroleum available to make more jet fuel. We're interested in the supply and demand for the finished product, jet fuel currently on the market. We can't conclude (E) is true from the stimulus.