How can I simplify finding positive odd solutions to the equation 17x+11y=1000?

  • Thread starter Thread starter MSG100
  • Start date Start date
  • Tags Tags
    Variables
AI Thread Summary
The discussion focuses on finding positive odd integer solutions for the equation 17x + 11y = 1000. Initial attempts involved using a Diophantine approach, yielding general solutions but not positive integers. A second method tested odd values of x within a specific range, resulting in three valid positive odd pairs: (9, 77), (31, 43), and (53, 9). To simplify the process, it was suggested to leverage the Diophantine solution by determining specific values of k that ensure both x and y remain positive and odd. Ultimately, the values of k identified were 177, 179, and 181 for achieving positive odd solutions.
MSG100
Messages
43
Reaction score
0
Problem:
Find all the positive integer solutions where x and y are odd numbers, to the equation: 17x+11y=1000

Attempt of solution:

First attempt:
With Diophantine equation have gotten the answers:

x=2000
y=-3000

and the general solutions will be:

x=2000-11k
y=-3000+17k

Now I don't know what to do.

Second attempt:
If I skip the Diophantine solution and do it like this:

y=(1000-11x)/17

Now I see that x has to be in the interval 0≤x≤58 if y should be positive.

If I test all the odd numbers in the interval I'll get 3 solutions when both x and y are positive and odd numbers. The solutions are:

(x, y) = (9, 77), (31, 43) and (53, 9)


This solutions (which should be the right answer) takes a lot of time because you have to test all odd numbers between 0 to 58 (29 different numbers).

I need help to find an easier solution.
 
Physics news on Phys.org
MSG100 said:
Problem:
Find all the positive integer solutions where x and y are odd numbers, to the equation: 17x+11y=1000

Attempt of solution:

First attempt:
With Diophantine equation have gotten the answers:

x=2000
y=-3000

and the general solutions will be:

x=2000-11k
y=-3000+17k

Now I don't know what to do.

Second attempt:
If I skip the Diophantine solution and do it like this:

y=(1000-11x)/17

Now I see that x has to be in the interval 0≤x≤58 if y should be positive.

If I test all the odd numbers in the interval I'll get 3 solutions when both x and y are positive and odd numbers. The solutions are:

(x, y) = (9, 77), (31, 43) and (53, 9)


This solutions (which should be the right answer) takes a lot of time because you have to test all odd numbers between 0 to 58 (29 different numbers).

I need help to find an easier solution.

If you don't want to check all those numbers you should use your Diophantine solution. You just have to figure out what values of k will make both x and y positive. There aren't that many.
 
  • Like
Likes 1 person
Thanks, that makes sense!

Then I just have following numbers k= 177, 178, 179, 180, 181 to make x and y positive and only k= 177, 179, 181 to make them positive AND odd.
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Back
Top