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

  • Context: MHB 
  • Thread starter Thread starter Albert1
  • Start date Start date
  • Tags Tags
    Ratio
Click For Summary
SUMMARY

The problem involves finding the ratio of two natural numbers \(a\) and \(b\) given the equation \(a \times b = 1364 + (a + b)\) with the conditions that \(a > b\) and either \(a\) or \(b\) is a perfect square. The solution reveals that \(a = 52\) and \(b = 26\), leading to the ratio \(a:b = 2:1\). The perfect square in this case is \(b\), which equals \(26\) (since \(5^2 = 25\) is the closest perfect square less than \(26\)).

PREREQUISITES
  • Understanding of natural numbers and their properties
  • Familiarity with algebraic equations and factorization
  • Knowledge of perfect squares and their identification
  • Basic skills in solving quadratic equations
NEXT STEPS
  • Study the properties of quadratic equations and their solutions
  • Learn about Diophantine equations and their applications
  • Explore methods for identifying perfect squares within integer ranges
  • Investigate the relationship between products and sums in algebraic expressions
USEFUL FOR

Mathematics students, educators, and anyone interested in solving algebraic equations involving natural numbers and perfect squares.

Albert1
Messages
1,221
Reaction score
0
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 $a:b$
 
Mathematics news on Phys.org
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 !
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K