Where is the mistake in my probability calculation for a 20cm string cut?

Thread starter songoku
Start date Sep 15, 2022
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Cut Probability String

AI Thread Summary

The user is seeking clarification on a probability calculation regarding the lengths of string pieces cut from a 20cm string. They calculated the probability of the shorter piece being between 8 and 10 cm as P(8 ≤ X < 10) = 2 . (1/20) = 1/10, but their teacher indicated the correct answer is 2/10. The misunderstanding stems from the fact that the shorter piece does not necessarily include a specific mark, which affects the probability calculation. The user acknowledges this clarification. The discussion highlights the importance of understanding the conditions affecting probability outcomes.

Sep 15, 2022

songoku

Homework Statement: Please see below

Relevant Equations: Continuous Uniform Distribution

I want to ask about part (c). This is what I did:

the length of the shorter piece should be 8 ≤ X < 10 so P (8 ≤ X < 10) = 2 . (1/20) = 1/10

But my teacher said the correct answer is 2/10. Where is my mistake?

Thanks

Last edited by a moderator: Sep 16, 2022

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Sep 15, 2022

hutchphd

Science Advisor

Homework Helper

The shorter piece of string does not necessarilly have the mark on it.

Sep 15, 2022

songoku

I understand. Thank you very much hutchphd

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