What is the smallest integer with a remainder of 1 when divided by 6, 8, and 10?

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Discussion Overview

The discussion revolves around finding the smallest integer greater than 1 that leaves a remainder of 1 when divided by the integers 6, 8, and 10. Participants explore various methods and reasoning behind the problem, including algebraic approaches and the concept of least common multiples.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant proposes that the answer is 121 but asks for clarification on how to solve the problem.
  • Another participant explains that the problem can be framed as finding a number n such that n = 6a + 1, leading to multiple equations that can be manipulated.
  • A different participant suggests finding the least common multiple of 6, 8, and 10 and then adding one to that result.
  • One participant details the algebraic manipulation leading to the conclusion that x=121, explaining the relationships between i, j, and k in the context of the equations derived from the problem.
  • Some participants express confusion about the complexity of the problem, questioning its classification as a middle school topic and discussing the level of mathematical understanding required.
  • There is a mention of the problem being more aligned with number theory, which some participants feel is not typically covered at the middle school level.
  • Participants also discuss the nature of the problem, suggesting it may be designed to challenge top performers in mathematics.
  • There is a light-hearted exchange regarding the identities of participants, with some confusion about their usernames and previous comments.

Areas of Agreement / Disagreement

Participants express differing views on the complexity of the problem and its appropriateness for middle school education. While some agree on the methods to find the solution, there is no consensus on the classification of the problem or the level of difficulty it presents.

Contextual Notes

Some participants note that the problem requires whole number solutions, which complicates its classification within typical algebraic frameworks. There is also mention of the challenge posed by the problem, suggesting it may not be straightforward for all students.

PrudensOptimus
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What is the smallest integer greater than 1 that leaves a remainder of 1 when divided by any of the integers 6, 8, and 10?

the answer is 121... how do you do this problem?
 
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You are looking for a number n such that n = 6a + 1 for some integer a. Similarly, you get two more equations, all equal to n. You can eliminate n from all of them, and you get two equations with three unknowns. The remaining freedom comes allows you to choose non-integers and also higher and higher integers, but you only take the smallest integer solution for n.
 
Can you explain how you got the equation?
 
You're looking for the least common multiple of 6,8, and 10, and then you'll want to add one.

There are many methods for finding the least common multiple.
 
Saying that the number, x, has remainder 1 when divided by 6, 8, and 10 means x= 6i+ 1, x= 8j+ 1, and x= 10k+ 1 for some i, j, k. Putting those together, 6i+ 1= 8j+ 1= 10k+ 1. Subtract 1 from each part: 6i= 8j= 10k. Divide each part by 2: 3i= 4j= 5k. Since 3, 4, and 5 are mutually prime, the smallest values that will work are i= 4*5, j= 3*5 and k= 3*4: in other words, 6i= 8j= 10k= 6*20= 4*15= 5*12= 120 and so x= 6i+ 1= 8j+ 1= 10k+1= 121.
 
Originally posted by HallsofIvy
Saying that the number, x, has remainder 1 when divided by 6, 8, and 10 means x= 6i+ 1, x= 8j+ 1, and x= 10k+ 1 for some i, j, k. Putting those together, 6i+ 1= 8j+ 1= 10k+ 1. Subtract 1 from each part: 6i= 8j= 10k. Divide each part by 2: 3i= 4j= 5k. Since 3, 4, and 5 are mutually prime, the smallest values that will work are i= 4*5, j= 3*5 and k= 3*4: in other words, 6i= 8j= 10k= 6*20= 4*15= 5*12= 120 and so x= 6i+ 1= 8j+ 1= 10k+1= 121.

Since when did they teach this in middleschool? This seems soo hard, seems like Number theory or some crap...

Where can I go for more help?
 
I know that lcm and gcf are covered in middle school, and that will get you the answer. (As I pointed out above.)

The horde of equations that Hurkyl used is more aptly described as basic algebra. (Although the exercise could certainly be described as a number theory problem.)
 
Originally posted by NateTG
I know that lcm and gcf are covered in middle school, and that will get you the answer. (As I pointed out above.)

The horde of equations that Hurkyl used is more aptly described as basic algebra. (Although the exercise could certainly be described as a number theory problem.)


I am not very good with number theories, because I don't deal much with those exercise:\
 
The problem is not actually high schol algebra because one of the constraints is that the answer contain only whole numbers, and there is no way to express that in high school algebra.

This is actually a question to pick out top performers. Some percentage of the top 1% of math brains will be able to figure out a procedure (something like what Hurkyl gave)to get an answer without knowing a general rule.
 
  • #10
Blarg, this is the second time (that I've noticed) that HallsofIvy has been accused of being me!
 
  • #11
Originally posted by Hurkyl
Blarg, this is the second time (that I've noticed) that HallsofIvy has been accused of being me!

Mea Culpa.

I get confused b/c you two Newmans look alike.
 
  • #12
One of us is being insulted!

(I'm just not sure which of us.)



Why the remark about "middle school"? Who said this was a middle school problem?
 

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