You cannot reach any of the specific conclusions provided here. We are told nothing about the possibility of cars running on potatoes. Perhaps they would run so slowly that it would cause traffic problems. Maybe only ships use potatoes. We just cannot say, given our limited information. Likewise, we cannot say anything about potato-based vehicles other than the fact that they are slow. Nothing can be said about the speed of cars, given the information that we have.

Since radios are a (i.e. one) type of signal-receiving device, they are not necessarily ones that are regulated by the government. It is said that some types of these devices are regulated, but that does not mean that any particular one kind (for instance, radios) is. It might be the case that only radar-receivers are regulated. Still, since it is the case that signal receiving devices are regulated by the government, there is a chance that radios would fall into that category. We can at least say that—and nothing more, pending further investigation and more details!

For this problem, you can reach one of the tentative conclusions that are provided among the optional answers. The key thing to note is that Harry is merely said to have "tragically died." Do not be tricked into thinking that Harry necessarily died by falling through one of the large holes discussed in the question. Perhaps he had a heartattack or was killed by another passenger. Either of these would have been tragic deaths as well.  It seems strange, but we can say that he might have flown on the plane. Even though they never have accidents, nothing is said that would imply that nothing tragic could ever happen on a plane.

For this question, you cannot infer anything specifically, for being "well-known" does not tell you one way or the other anything specifically about Thomas' sales. He might be well known because he is a very, very bad author or a controversial one. This would not lead to any sales necessarily. Thus, you need to choose the very boring but most correct, "None of the others."

Be careful! This does not say that the strong will necessarily be victorious. It says only that if someone is victorious, that person must be strong. The language is a bit reversed, but it only communicates that sense. Now, if Thomas is hardheaded, he is also strong, as can be concluded from "All hardheaded people are strong." Beyond this, we cannot say anything more conclusive than he could be victorious since he has the necessary but insufficient characteristic of being strong.

First, let's analyze the sentence about the purchase of the stallion. Paula forced her husband to buy an animal that is expensive to keep. Now, based on the second sentence, all such purchases lead only to one of two outcomes: poverty or a family breakup. Since they remained married for the rest of their lives, we must say that the "other option" was all that held, namely that they lived in poverty. In any case, this is what can be concluded from the statements provided.

Let's rewrite this in a semi-mathematical manner, using the following shorthand:

E: (Books read by) English Majors

A: (Books read by) Anthropology Majors

CS: (Books read by) Computer Science Majors

B: (Books read by) Biology Majors

We know the following:

(1) E > A

(2) CS < B

(3) B < E

Now, we can combine (2) and (3):

CS < B < E

Let's rewrite that:

E > B > CS

Now, while we know that E > A, we cannot say anything about the relative position of A. It could be all the way below the computer science majors, it could be between biology and computer science, etc. None of the answers are acceptable.

Let's rewrite this in a semi-mathematical way:

C: Chemistry difficulty

PS: Political science difficulty

PH: Physics difficulty

B: Biology difficulty

We know the following from our prompt:

(1) C > PS

(2) PS < PH (or: PH > PS)

(3) PH > B

However, note that we cannot really say much else. We do not know the relative positions of biology and political science, except that they are easier than physics. Likewise, while we know that chemistry is harder than political science, we cannot say anything about its relationship to physics. (Likewise, this means that we cannot say anything about its relationship to biology). Thus, the answer is "none of the others."

This question is meant to trick you. Learn to pay close attention to details. If Mary is a banker, all that we could say is that she has a greater chance (not necessity) of eating pork chops than would someone who is an accountant. We cannot say anything about the relationship between bankers and the water-drinking of accountants or any others. Thus, the only acceptable answer is "none of the other answers."

Just follow the logic of the strange expressions. Since Bob is a creep, he is also a ring-rang. Now, all zip-doodles are mishmashes. Thus, some ring-rangs are mishmashes. Thus we can say that all creeps are ring-rangs, some of which are mishmashes. Thus, some creeps are mishmashes.