Happy to help. Let's first take a look at the stimulus.
The stimulus is saying that the flight times to Mars and Phobos are the same, but flights to Phobos would require less than half the fuel that flights to Mars would require. The argument concludes Phobos, not Mars, should be our next step in space exploration.
This is an interesting paradox, so it's good to think about why flying to Phobos would require so much less fuel than flying to Mars. One potential reason flights to Phobos require less fuel is because Phobos is probably smaller since it's a moon, and there's probably way less gravity on Phobos, which means flying in general requires less fuel than on Mars.
Smaller (moon and not planet) - >less overall mass - ->weaker gravity - >less fuel required
Since the stimulus has such a weird paradox (same flight times but different fuel requirements), it's always good for us to anticipate why that paradox is there.
The question asks, "Which one of the following, if true, would most help to explain the difference in fuel requirements?"
(E) says, "Lift off for the return trip from Phobos requires much less fuel than that from Mars because of Phobos' weaker gravitational pull."
(E) matches our anticipation really well, and this would help quite a bit to explain why flying to Mars would require more than twice the fuel, so this is our correct answer choice.
Does this make sense? Let us know if you have any more questions?
#JWSeptember 22, 2019
I was able to narrow it down to answer choices A and E. I chose E simply because of the direct reference to lower fuel requirements due to less of a gravitational pull; however, how can we confidently eliminate answer choice A? I was tempted to infer that less equipment equals less weight which would in turn solve to difference in fuel dilemma/paradox? This is just causing me issue as it wastes time going back and forth. Thanks for the help.. preparing for the October 2019 exam!
IrinaSeptember 22, 2019
@Jwebb,
Notice that (A) tells us that MORE equipment is required to explore Phobos, thus suggesting that more fuel would be required assuming that more equipment equals more weight, whereas the argument tells us that less fuel is needed for a Phobos expedition. Hence (A) actually weakens the argument rather than helps explain the paradox.
Good luck on October exam!
alicat6July 21, 2020
I did not choose E because it reference the return flight, when the passage only referenced fuel to get to Mar/Phobos. I thought it was a trap answer, so I did not choose it. How do you know when you are supposed to be super nitpicky with every word on the LSAT and when you aren't?
