LSAT Explanation PT 32, S1, Q7: If you have no keyboarding skills

LSAT Question Stem

If the statements above are true, which one of the following must be true? 

Logical Reasoning Question Type

This is a Must Be True question. 

Correct Answer

The correct answer to this question is C. 

LSAT Question Complete Explanation

Let's first understand the passage and its logical structure. The passage states two conditions:

1. If you have no keyboarding skills at all (No KS), you will not be able to use a computer (Not AUC).

2. If you are not able to use a computer (Not AUC), you will not be able to write your essays using a word processing program (Not WEWP).

To make this more relatable, let's use a simple example. Imagine keyboarding skills are like the ability to ride a bike, using a computer is like riding a bike to a specific destination, and writing essays using a word processing program is like successfully reaching that destination. If you can't ride a bike at all, you won't be able to ride it to the destination, and if you can't ride the bike to the destination, you won't reach it.

Now, let's represent these conditions using formal logic notation:

1. No KS -> Not AUC

2. Not AUC -> Not WEWP

We can chain these conditions together:

No KS -> Not AUC -> Not WEWP

Now, let's identify the question type and what it's asking us to do. This is a Must Be True (MBT) question, which means we need to find the answer choice that must be true based on the given information.

Let's analyze each answer choice:

a) If you have some keyboarding skills (KS), you will be able to write your essays using a word processing program (WEWP).

- This answer choice is a Mistaken Negation of the chain inference and is incorrect. The correct diagram would be: KS -> AUC -> WEWP, but this answer choice only shows KS -> WEWP.

b) If you are not able to write your essays using a word processing program (Not WEWP), you have no keyboarding skills (No KS).

- This answer choice is a Mistaken Reversal of the chain inference and is incorrect. The correct diagram would be: No KS -> Not AUC -> Not WEWP, but this answer choice shows Not WEWP -> No KS.

c) If you are able to write your essays using a word processing program (WEWP), you have at least some keyboarding skills (KS).

- This is the correct answer, as it is the contrapositive of the chain inference. The contrapositive is: WEWP -> KS, which is equivalent to the original chain.

d) If you are able to use a computer (AUC), you will probably be able to write your essays using a word processing program (WEWP).

- This answer choice is a Mistaken Negation of the second sentence and is incorrect. The correct diagram would be: AUC -> WEWP, but this answer choice only shows AUC -> Probably WEWP, which is not certain.

e) If you are not able to write your essays using a word processing program (Not WEWP), you are not able to use a computer (Not AUC).

- This answer choice is a Mistaken Reversal of the second sentence and is incorrect. The correct diagram would be: Not AUC -> Not WEWP, but this answer choice shows Not WEWP -> Not AUC.

So, the correct answer choice is (C): If you are able to write your essays using a word processing program (WEWP), you have at least some keyboarding skills (KS).