Logical Reasoning · Main Conclusion

PrepTest 126 · Section 3 · 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

Main Conclusion

The one idea it tests

When an argument says 'a common belief is mistaken,' the point is the rejection of that belief, and the research is the support.

The basic logic

Find the sentence the rest supports. The research finding is a patty: it backs up the claim that the old belief is wrong. Don't grab the finding itself, and don't grab what the old sources said.

Tiny words that decide it

“although”
“mistaken”
“has shown”

Playground logic

Priya's top bun is that the belief about purple markers is wrong. Her patty is the sun test showing purple stays bright. The old art book is background: it explains where the belief came from.

Step 2 · The kid story

The Purple Marker Myth

For years, kids at school have believed you should never use purple markers on the class banner. The old art book in the supply closet says purple ink fades fast in sunlight, so it ruins banners. Everyone listens to the art book. Priya didn't. "That belief is wrong," she told the class. "I taped purple stripes on the sunniest window for a whole month. They stayed just as bright as the blue and green ones." Kevin raised his hand. "So purple doesn't fade?" "My test shows it doesn't," Priya said, "and that's why the old rule is wrong." Marcus, who had already hidden every purple marker, quietly put them back. The new banner had a giant purple dinosaur on it. Kevin was thrilled.

Step 3 · Try the model question

Priya: For years, students have believed purple markers should be kept off the class banner. The old art book encouraged this belief by saying purple fades quickly in sunlight. But the belief is wrong. My month-long window test proved that purple stays as bright as other colors.

Which statement best captures the main point Priya is arguing for?

Step 4 · The courtroom tale

The Bridge Toll Myth

In a fictional town, drivers long believed you must slow to a crawl on the old wooden bridge. The town guidebook said the boards were rotten and could give way. Mr. Whitfield represented a driver ticketed for driving at normal speed. "Your Honor, the belief that this bridge needs a crawl is mistaken. Engineers tested every board last spring. They're solid as stone." The prosecutor waved the guidebook. "But the guidebook says..." "The guidebook is why people believe it," said Mr. Whitfield. "The engineers' test is my evidence. My point is simple: the belief is wrong." The judge peered over her glasses. "Point taken. Ticket dismissed."

Step 5 · Work the real question

Open PrepTest 126, Section 3, Question 13 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Spot the structure: a common belief, where it came from, a judgment on the belief, and research backing that judgment. Ask which sentence the others serve; use the Why test ('Why believe that? Because...'). Evidence and background are never the point. Pick the answer that matches the sentence everything else supports, in its own scope, no bigger and no smaller.