Unit 6 · Identifying Sufficient Information

Ravi vs Luca — Whose Reasoning Holds?

Lesson 7 of 12

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One fact: most Bulbo trees are in the Manu Forest in Peru. Two deductions: Ravi says a random Bulbo tree is probably in Peru, and Luca says a random Manu Forest tree is probably a Bulbo. Only one of them is right — and figuring out which one requires understanding the difference between "most X are in Y" and "most Y are X." This is one of the most important logical distinctions in OC TS.

Chapters

0:00Introduction
0:25The Question
1:09Step 1: Check Ravi's reasoning
1:33Step 2: Check Luca's reasoning
2:07Step 3: Compare and confirm answer
2:37Correct answer

Question

The majority of the Bulbo trees in the world are in the Manu Forest in Peru.

Ravi: "So if you were to randomly choose a tree from all the Bulbo trees in the world, it would probably be in Peru."

Luca: "And if you were to randomly choose a tree in the Manu Forest, it would probably be a Bulbo tree."

If the information in the box is true, whose reasoning is correct?

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