Find Ratio of a:b When $1364+(a+b)=a\times b$

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Discussion Overview

The discussion revolves around finding the ratio of two natural numbers \(a\) and \(b\) under specific conditions, including their product equating to a sum involving 1364, and the stipulation that either \(a\) or \(b\) is a perfect square. The scope includes mathematical reasoning and problem-solving related to number theory.

Discussion Character

  • Mathematical reasoning, Debate/contested

Main Points Raised

  • Some participants propose that either \(a\) or \(b\) must be a perfect square, but it is not specified which one it is.
  • Participants reiterate the conditions that \(a\) and \(b\) are natural numbers with \(a > b\) and that their product equals \(1364 + (a + b)\).
  • There are corrections made by participants, but the specific nature of these corrections is not detailed.

Areas of Agreement / Disagreement

There is no consensus on which number, \(a\) or \(b\), is the perfect square, and the discussion remains unresolved regarding the specific values of \(a\) and \(b\) and their ratio.

Contextual Notes

The discussion does not clarify the assumptions regarding the nature of the perfect square or the methods to derive the ratio \(a:b\). There may be missing mathematical steps or definitions that are not fully explored.

Albert1
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if :
(1)$a,b\in N $, and $a>b$
(2)$a\times b =1364+(a+b)$
(3) eather $a$ or $b$ is a perfect square
can you tell which one is a perfect square ? ( $a$ or $b$ ?),and please find $a:b$
 
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Albert said:
if :
(1)$a,b\in N $, and $a>b$
(2)$a\times b =1364+(a+b)$
(3) eather $a$ or $b$ is a perfect square
can you tell which one is a perfect square ? ( $a$ or $b$ ?),and please find $a:b$

$ab-a-b = 1364$
or $ab-a-b+1 = 1365$
or $(a-1)(b-1)= 1365= 3 *5 * 7 * 13$
now we get 3 choices
choice 1
$ a= 92, b= 16$ and ratio $a::b = 23::4$
choice 2
$ a= 40, b = 36$ and $a::b = 10::9 $
choice 3
$a = 256, b= 8$ and $a::b= 32::1$
 
kaliprasad said:
$ab-a-b = 1364$
or $ab-a-b+1 = 1365$
or $(a-1)(b-1)= 1365= 3 *5 * 7 * 13$
now we get 3 choices
choice 1
$ a= 92, b= 16$ and ratio $a::b = 23::4$
choice 2
$ a= 40, b = 36$ and $a::b = 10::9 $
choice 3
$a = 256, b= 8$ and $a::b= 32::1$

we get 4 choices
an you got two points
10:9 and 23:4
 
Albert said:
we get 4 choices
an you got two points
10:9 and 23:4

Albert,

Please use the spoiler tags when posting anything pertaining to a solution. Thanks! :)
 
Albert said:
we get 4 choices
an you got two points
10:9 and 23:4

I got 3 choices and missed the 4th
$b= 4,a = 356$ giving $a::b= 89::1$
 
kaliprasad said:
I got 3 choices and missed the 4th
$b= 4,a = 356$ giving $a::b= 89::1$
correction:
$a:b=32:1$ this answer is not correct
$a:b=89:1$ this answer is not correct
$a:b=23:4$ this answer is correct
$a:b=10:9$ this answer is correct
 
Albert said:
correction:
$a:b=32:1$ this answer is not correct
$a:b=89:1$ this answer is not correct
$a:b=23:4$ this answer is correct
$a:b=10:9$ this answer is correct
it should be
$a=456,b=4$ ratio = $114::1$
$a=196,b=8$ ratio = $49::2$
 
kaliprasad said:
it should be
$a=456,b=4$ ratio = $114::1$
$a=196,b=8$ ratio = $49::2$
bingo !
 

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