Logical reasoning PrepTest 139 · Section 1 · Question 21

Incorrect. While Nobel prize winners are typically professional scientists, that leaves open the possibility that some are amateur scientists, and it could be that all amateur scientists who made a significant contribution won prizes. There's no discussion of the relative sizes of these groups, so one could completely include the other.

Incorrect. The typical winner of a Nobel prize for science is a professional scientist. While they are "often" motivated by things other than love of discovery, it's possible that most are motivated by such a love, or that they're all motivated in part by a love of discovery on top of other motivations.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
All Nobel prize winning scientists have significantly contributed to science
Some amateur scientists have significantly contributed to science
Some pro scientists are motivated by money or fame
Amateur scientists are motivated only by love of discovery

Answer Anticipation:
If you tried to diagram these statements out, there's nothing wrong with that—there are conditionals and quantified statements, and you could represent them that way. However, the way that these statements overlap isn't nice, and some of the statements are hard to diagram precisely (that last one, for instance), so it could be better to just get a general understanding of what's going on and look for statements that discuss the same groups.

Here, there are three groups—amateur scientists, professional scientists, and Nobel prize winning scientists (which are usually the latter). We get the strongest statements about the Nobel prize winners, but there's only one statement about them, so drawing an inference about that group is unlikely. The statements about professional scientists are weak, so it's hard to see an inference that can be drawn about them.

The two statements about amateur scientists, however, are relatively strong and show some overlap. We know that all amateurn scientists are motivated by love of science "alone," and that they have been responsible for some important scientific discoveries. As such, we can say that some such discoveries were motivated by love of discovery.

Answer Explanation:
Since amateur scientists are motivated by love of discovery alone, and they've also made many significant contributions to science, those contributions must be motivated by love of discovery. This answer is supported by the stimulus.

Key Takeaway:
When you get a mix of statements in a Must Be True question that don't have a clear conditional structure, diagramming them out can help you wrap your head around them, but try to identify the strongest statements that overlap. Doing so will likely lead to the inference while allowing you to ignore all of the distractions.

Incorrect. There's no statement that compares the contributions of the two groups. While the professionals may have more Nobel prizes to their names, there's no indication that that's a measure of overall contribution to science.

Incorrect. The likelihood of any individual scientist making a contribution to science isn't discussed, let alone tied to motivation.