LSAT 123 | Section 3 | Logical Reasoning: Q17

LR Question 17 Explanation

QUESTION TEXT: When exercising the muscles in one’s back, it is important…

QUESTION TYPE: Necessary Assumption

CONCLUSION: To keep a healthy back it is important to exercise both sides of your back equally.

REASONING: It is important that muscles on both sides of your spine pull equally on the spine and therefore that muscle development is balanced.

ANALYSIS: This argument is assuming that equal muscle pull requires equal exercise.

On necessary assumption questions your main job is to look for where the conclusion slipped in a new concept which wasn’t mentioned in the reasoning. Here, exercise was that new concept.

___________

1. The author wasn’t saying that equal exercise was sufficient to align the back. They just said it was important. Maybe other things are also required.
2. CORRECT. If this isn’t true, then the conclusion has no support.
   Negation: Exercising the muscles on opposite sides of the spine unequally doesn’t lead to unbalanced muscles.
3. This is like A. The author was saying that exercising the sides equally was important. They weren’t saying it was the only thing you need to do!
4. This goes too far. Taken literally, this means that if you do even a single wrong exercise, you will permanently hurt your back. That’s insane! And more importantly, this extreme answer isn’t necessary for the argument.
   Negation: It is generally bad to exercise muscles unequally, but it’s possible to do it once or twice without permanent damage.
5. The author didn’t say how often exercise is required. It’s possible you don’t need to do it daily!
   Negation: You can exercise once every two days and still have a healthy back.