I looked around the internet and there is a serious lack of practice available for basic conditional reasoning and logic concepts, fundamental skills needed to master the LSAT. To address this, here is a LSAT conditional reasoning and logical inferences quiz, the first of a series of LSAT quizzes to help round out your LSAT prep.
This quiz focuses on diagramming conditional statements and making some key inferences commonly found on the LSAT. If you want to brush up before the quiz, our totally free intro conditional logic lesson is here. Answers to the LSAT quiz questions are below. Enjoy!
– Evan Jones
Conditional Reasoning Questions
Level 1
super basic diagramming for if-then statements- make a diagram for the original statement and the contrapositive.
1. If you are a wild penguin, then you live in the southern hemisphere.
2. If you are a penguin, then you cannot fly.
Level 2
diagramming statements with ‘only if”, ‘must’, and ‘required’- make a diagram for the original statement.
3. Only if you are a wizard can you use a wand.
4. You must be a hardened criminal to commit burglary.
5. You are required to take a test to pass driving school.
LEARNING LSAT CONDITIONAL REASONING
If you feel you need to brush up on conditional reasoning, we have a great free intro lesson here. For an in-depth look at conditional logic and every other subject related to LSAT logical reasoning, we recommend the Powerscore Logical Reasoning Bible. The chapter on conditional reasoning is great and contains lots of drills, real LSAT questions, and good tips.
Level 3
diagramming statement with ‘unless’, ‘without’, and ‘except’- make a diagram for the original statement and the contrapositive.
6. You can’t be a pilot unless you have good vision.
7. You are nothing without somebody to love.
8. Except for mermaids, humans cannot breathe under water.
Level 4
contrapositives with ‘and’ and ‘or’- write out and make a diagram of the the contrapositive of each statement.
9. If you are bitten by a radioactive spider, then you are super strong and can make webs.
10. If you took the brown acid, then you are freaking out or believe you are a canary.
Level 5
super basic inferences- choose the inference that can be properly made from the premises.
11. If you are a penguin then you cannot fly. If you cannot fly then you are a mainly terrestrial species.
Answer choices:
a. If you are a mainly terrestrial species then you cannot fly.
b. If you are a penguin then you are mainly a terrestrial species.
c. If you are not a penguin then you can fly.
12. If you found unobtainum, then you are mining on Pandora. You are are actually mining on one of the moon’s other than Pandora that surround the planet Polythemus.
Answer choices:
a. You found unobtainium.
b. You did not find unobtainum.
c. You found something other than obtainium.
Level 6
More advanced inferences
13. There is some debate as to whether great-crested grebes are common in Swansea, but it is known that most grebes live in North Savoy and some grebes live within a mile of a lake. Also, most grebes inhabit boggy areas.
Choose the inference that can be properly made from the premises:
a. Some grebes in Swansea live within a mile of a lake.
b. Some grebes in North Savoy live within a mile of a lake.
c. Some grebes in North Savoy inhabit boggy areas.
14. Most unobtainum is only found in the found in the lush jungle covered areas of Pandora. Some of the miners are out seeking unobtainum in the arid regions, and some of them located unobtainium. Overall, a large quantity of unobtainum was discovered and mined on Pandora in the last month.
List any of the following which could be true.
a. All of the large quantity of unobtainium from last month was discovered and mined in the arid regions of Pandora.
b. Most of the large quantity of unobtainium from last month was discovered in the jungle regions of Pandora.
c. None of the large quantity of unobtainium from last month was discovered in the jungle regions of Pandora.
d. Not all of the large quantity of unobtainum was discovered in the arid regions of Pandora.
e. All of the unobtainium mined in Pandora last month was from the jungle regions of Pandora.
Answers:
1. If you are a wild penguin, then you live in the southern hemisphere.
Diagram: WP —–> SH
Contrapositive: Not SH —-> Not WP
Alternative Diagram of contrapositive: SH ——> WP
2. If you are a penguin, then you cannot fly.
Diagram: P —–> Not F
Alternative diagram: P —–> F (from here on out we are going to stick with the slash style of diagramming).
3. Only if you are a wizard can you use a wand.
Diagram: UWnd ——> Wiz
4. You must be a hardened criminal to commit burglary.
Diagram: CB —–> HC
5. You are required to take a test to pass driving school.
Diagram: PDS ——> TT
6. You can’t be a pilot unless you have good vision.
Diagram: P —–> GV (could be phrased as an if-then statement: if you are a pilot then you have good vision)
Contrapostive GV ——> P
Tips: ‘unless’, ‘without’, and ‘except’ can be a little tricky. If you can’t do it intuitively, here is the mechanical approach: take whatever comes after those phrases and put it in the necessary condition spot. The rest is negated then put in the sufficient condition spot.
7. You are nothing without somebody to love.
N —–> STL (could be phrased as an if-then statement: If you are not nothing then you have somebody to love)
STL —–> N
8. Except for mermaids, humans cannot breathe under water.
HBW ——> M (could be phrased as an if-then statement: If you are a human that breathes under water, then you are a mermaid)
M ——-> HBW
9. If you are bitten by a radioactive spider, then you are super strong and can make webs.
Contrapositive: If you are not super strong or cannot make webs, then you were not bitten by a radioactive spider.
Diagram: SS or MW ——–> BRS
10. If you took the brown acid, then you are freaking out or believe you are a canary.
Contrapositive: If you don’t believe you are and canary and you are not freaking out, then you did not take the brown acid.
Diagram: BC and FO ——–> TBA
Tip: Note that these ‘and’ switches to ‘or’ in the contrapostive and vice versa. This also the case with making contrapositives with the conjunctions ‘and’ and ‘or’.
11. If you are a penguin then you cannot fly. If you cannot fly then you are a mainly terrestrial species.
Correct answer: b.
12. If you found unobtainum, then you are mining on Pandora. You are are actually mining on one of the moon’s other than Pandora that surround the planet Polythemus.
Correct answer: b.
13. There is some debate as to whether great-crested grebes are common in Swansea, but it is known that most grebes live in North Savoy and some grebes live within a mile of a lake. Also, most grebes inhabit boggy areas.
Choose the inference that can be properly made from the premises:
Correct answer: c. This can be a tricky one. The tough part is see that when most members of a group have some characteristic, and most members of the same group also share another characteristic, then there has to be some overlap: at least one grebe is going to have to live in North Savoy and inhabit a boggy area.
14. Most unobtainum is only found in the found in the lush jungle covered areas of Pandora. Some of the miners are out seeking unobtainum in the arid regions, and some of them located unobtainium. Overall, a large quantity of unobtainum was discovered and mined on Pandora in the last month.
List any of the following which could be true:
a, b, c, d, and e could all be true. This was designed to be a lesson in the variety of possibilities when you don’t have a lot of information. Though we can’t properly draw any of these inferences from the premises, we can’t eliminate any of them either. To me, ‘a.’ is toughest and the one a lot of LSAT beginners trip up on. The tricky thing to realize is that the term ‘some’ can indeed include the quantity ‘all’, even though in everyday speech we tend not to use it when ‘all’ is a possibility.
I hope you enjoyed this short quiz! Please check back for more soon. We are happy to clarify anything in the comments. This is our first attempt at quiz making, so also please let us know if you want harder questions, easier, or what have you. We are also open to suggestions for quiz subjects- if you have an area where you need work, please let us know!
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2 Comments
Can someone help me to understand number 12?
The only way you mined unobtanium is if you mined on Pandora. Since you are not on Pandora then you did not mine unobtanium. You can know this for sure. You cannot no whether or not you mined something else from the information given.