Logical Reasoning · Strengthen

PrepTest 113 · Section 4 · Question 13

Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.

Step 1 · Pre-Question Guidance · read this first

Question type

Strengthen

The one idea it tests

In a Strengthen EXCEPT question, four answers help the cause-and-effect claim and one is just a fact that does not help.

The basic logic

Name the suspected cause and the effect. Helpers do things like: show a way the cause could work, rule out other causes, show more exposure, or show the effect came after the cause. The answer is the one that does none of these.

Tiny words that decide it

“EXCEPT”
“each”
“caused”

Playground logic

Lulu's top bun says scooter pushing caused the left-shoe scuffs. Helpers rule out other causes or show the timing fits. The odd one out is a fact about how common scooters are, which tells us nothing about the scuffs.

Step 2 · The kid story

The Left-Shoe Mystery

Lulu noticed something strange. Five kids in her class had scuff marks on only their left shoe. "Something is rubbing one side," she said. She checked each kid. Every one rides a scooter to school and pushes off with the left foot. Lulu wrote on her clipboard: scooter pushing causes left-shoe scuffs. Marcus wanted to help. "Here's support: the scooter deck has rough grip tape on the edge!" Nadia said, "And at recess, their other games wear both shoes evenly." Owen added, "The scuffs showed up right after they got scooters." Then Kevin said, "Lots of kids in town own scooters!" Lulu looked at him. "Kevin, that is true. But it doesn't help us explain these left shoes at all." Kevin shrugged. "Dinosaurs didn't need scooters."

Step 3 · Try the model question

Five kids had scuffs on only their left shoes. Each one rides a scooter and pushes off with the left foot. Lulu concluded that pushing off on the scooter caused the scuffs.

If true, every choice below would back up Lulu's conclusion EXCEPT:

Step 4 · The courtroom tale

The Case of the Faded Left Sleeve

A bus driver sued the uniform maker. "My left sleeve fades and no other part does." The maker's lawyer smirked. "Prove our fabric is the problem." Mr. Whitfield listed his helpers. "The driver's window is on the left, and sunlight hits that arm all day. His right side sits in shade. The fading started the month he got the new route with more sun. And this fabric fades fast in sunlight." Then a junior lawyer jumped up. "Also, Your Honor, most people in this city wear uniforms!" Silence. Mr. Whitfield sighed kindly. "True, but it tells us nothing about this sleeve." The judge struck that remark. "Four helpers, one bystander."

Step 5 · Work the real question

Open PrepTest 113, Section 4, Question 13 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Write the cause and the effect in a few words. Read each answer and ask whether it shows how the cause works, removes another cause, shows more contact with the cause, or confirms the timing. Put a check next to each helper. The correct answer is the one that leaves the cause-and-effect link untouched, usually a broad general fact about how common something is.