Day of the Week Puzzle: Solving with Modular (Clock) Arithmetic

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Homework Help Overview

The problem involves determining the day of the week that falls 4^1000 days from a Sunday, utilizing concepts from modular arithmetic.

Discussion Character

  • Exploratory, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the cyclical nature of weeks and the relevance of modular arithmetic in finding remainders when dividing by 7. Some explore patterns in the powers of 4 modulo 7.

Discussion Status

There are various lines of reasoning being explored, including the identification of patterns in remainders and the implications of the week’s cyclical nature. Some participants express gratitude for the insights shared, indicating a collaborative atmosphere.

Contextual Notes

Participants are working within the constraints of modular arithmetic and the specific problem setup, focusing on the implications of large exponentiation in relation to a weekly cycle.

Maw615
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I have this question and you need to use Modular (Clock) Arithmetic to solve it. If there is any work I need to know that. If you don't know the answer, is there anyway you can just tell me the process of how to do it? Thank you very, very much! Here is the problem:

What day of the week will 4^1000 days from a Sunday?
 
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Have you considered that the week always repeats itself after seven days. Seven days after Sunday it's Sunday again, also after 7000000000 days. Consequently 700000000000000002 days from a Sunday it will be Tuesday. Would that help?
 
Well after looking at this, I noticed a pattern. When you square 4 the first time, the remainder of that number divided by 7 is 2. when you cube 4 the remainder is 1. When you put it to the 4th the remainder is 4, then this pattern repeats. So then since it is to the 1000, it would be 4 days after sunday.
 
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Thank you very, very much for your help! :smile:
 

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