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Ratio when one entity is 0.

1

$begingroup$

What is the ratio between boys and girls in a group with 30 boys and 0 girls?
Is it 1:0, 30:0 or something involving infinity and undefined?

Can somebody help me out here?

infinity

share|cite|improve this question

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

asked Jun 22 '12 at 14:01

user33984

$endgroup$

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  It’s undefined.
  $endgroup$
  – Brian M. Scott
  Jun 22 '12 at 14:02
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  possible duplicate of Division by zero, or one of these other fine results
  $endgroup$
  – MJD
  Jun 22 '12 at 14:08
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Also closely related: math.stackexchange.com/q/43251/622
  $endgroup$
  – Asaf Karagila♦
  Jun 22 '12 at 14:10
  

  
  
  
  


• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  $begingroup$
  @Brian: is it really though? I prefer to identify ratios not with fractions, but with something like projective space: I would say that for any two (nonempty) groups of children with no girls, the ratio of boys to girls are the same. Only in the case of $0:0$ would I really think that the ratio is undefined.
  $endgroup$
  – Willie Wong
  Jun 22 '12 at 14:17
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  @Cameron: That it’s a bad problem, and that they should say so.
  $endgroup$
  – Brian M. Scott
  Jun 22 '12 at 18:26
  

  
  
  
  

 | 
show 6 more comments

1

$begingroup$

What is the ratio between boys and girls in a group with 30 boys and 0 girls?
Is it 1:0, 30:0 or something involving infinity and undefined?

Can somebody help me out here?

infinity

share|cite|improve this question

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

asked Jun 22 '12 at 14:01

user33984

$endgroup$

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  $begingroup$
  It’s undefined.
  $endgroup$
  – Brian M. Scott
  Jun 22 '12 at 14:02
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  possible duplicate of Division by zero, or one of these other fine results
  $endgroup$
  – MJD
  Jun 22 '12 at 14:08
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Also closely related: math.stackexchange.com/q/43251/622
  $endgroup$
  – Asaf Karagila♦
  Jun 22 '12 at 14:10
  

  
  
  
  


• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  $begingroup$
  @Brian: is it really though? I prefer to identify ratios not with fractions, but with something like projective space: I would say that for any two (nonempty) groups of children with no girls, the ratio of boys to girls are the same. Only in the case of $0:0$ would I really think that the ratio is undefined.
  $endgroup$
  – Willie Wong
  Jun 22 '12 at 14:17
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  @Cameron: That it’s a bad problem, and that they should say so.
  $endgroup$
  – Brian M. Scott
  Jun 22 '12 at 18:26
  

  
  
  
  

 | 
show 6 more comments

$begingroup$

What is the ratio between boys and girls in a group with 30 boys and 0 girls?
Is it 1:0, 30:0 or something involving infinity and undefined?

Can somebody help me out here?

infinity

share|cite|improve this question

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

asked Jun 22 '12 at 14:01

user33984

$endgroup$

share|cite|improve this question

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

asked Jun 22 '12 at 14:01

user33984

share|cite|improve this question

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

asked Jun 22 '12 at 14:01

user33984

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

edited Jun 22 '12 at 18:44

Arturo Magidin

267k34591922

2 Answers
2

active

oldest

votes

2

$begingroup$

Here is a discussion on the topic. I tend to agree with Willie, myself, and would in this case say that it was $1:0$--in words, "for every boy in the group, there is no girl in the group"--which, thought of in this way, would be conceptually the same as $30:0$, but "reduced". Evidently, though, there is disagreement on this issue. My recommendation is that you try to determine which view is espoused by your text(s) and instructor(s), and stick by that.

share|cite|improve this answer

edited Dec 21 '13 at 17:32

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

$endgroup$

add a comment | 

1

$begingroup$

As was mentioned by others, it is undefined. If you want the ratio "of A to B" then this means you want $|A|/|B|$. E.g. the ratio of Boys to Girls is the number of boys divided by the number of girls. Hence, the ratio makes sense if and only if $|B|$ is not zero, since division by 0 is undefined.

Note: this means the ratio of 30 boys to 0 girls is undefined, but the ratio of 0 girls to 30 boys is defined (and is 0).

share|cite|improve this answer

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106

$endgroup$

add a comment | 

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2

$begingroup$

Here is a discussion on the topic. I tend to agree with Willie, myself, and would in this case say that it was $1:0$--in words, "for every boy in the group, there is no girl in the group"--which, thought of in this way, would be conceptually the same as $30:0$, but "reduced". Evidently, though, there is disagreement on this issue. My recommendation is that you try to determine which view is espoused by your text(s) and instructor(s), and stick by that.

share|cite|improve this answer

edited Dec 21 '13 at 17:32

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

$endgroup$

add a comment | 

2

$begingroup$

Here is a discussion on the topic. I tend to agree with Willie, myself, and would in this case say that it was $1:0$--in words, "for every boy in the group, there is no girl in the group"--which, thought of in this way, would be conceptually the same as $30:0$, but "reduced". Evidently, though, there is disagreement on this issue. My recommendation is that you try to determine which view is espoused by your text(s) and instructor(s), and stick by that.

share|cite|improve this answer

edited Dec 21 '13 at 17:32

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

$endgroup$

add a comment | 

$begingroup$

Here is a discussion on the topic. I tend to agree with Willie, myself, and would in this case say that it was $1:0$--in words, "for every boy in the group, there is no girl in the group"--which, thought of in this way, would be conceptually the same as $30:0$, but "reduced". Evidently, though, there is disagreement on this issue. My recommendation is that you try to determine which view is espoused by your text(s) and instructor(s), and stick by that.

share|cite|improve this answer

edited Dec 21 '13 at 17:32

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

$endgroup$

share|cite|improve this answer

edited Dec 21 '13 at 17:32

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

answered Jun 22 '12 at 18:43

Cameron BuieCameron Buie

87k773161

1

$begingroup$

As was mentioned by others, it is undefined. If you want the ratio "of A to B" then this means you want $|A|/|B|$. E.g. the ratio of Boys to Girls is the number of boys divided by the number of girls. Hence, the ratio makes sense if and only if $|B|$ is not zero, since division by 0 is undefined.

Note: this means the ratio of 30 boys to 0 girls is undefined, but the ratio of 0 girls to 30 boys is defined (and is 0).

share|cite|improve this answer

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106

$endgroup$

add a comment | 

1

$begingroup$

As was mentioned by others, it is undefined. If you want the ratio "of A to B" then this means you want $|A|/|B|$. E.g. the ratio of Boys to Girls is the number of boys divided by the number of girls. Hence, the ratio makes sense if and only if $|B|$ is not zero, since division by 0 is undefined.

Note: this means the ratio of 30 boys to 0 girls is undefined, but the ratio of 0 girls to 30 boys is defined (and is 0).

share|cite|improve this answer

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106

$endgroup$

add a comment | 

$begingroup$

As was mentioned by others, it is undefined. If you want the ratio "of A to B" then this means you want $|A|/|B|$. E.g. the ratio of Boys to Girls is the number of boys divided by the number of girls. Hence, the ratio makes sense if and only if $|B|$ is not zero, since division by 0 is undefined.

Note: this means the ratio of 30 boys to 0 girls is undefined, but the ratio of 0 girls to 30 boys is defined (and is 0).

share|cite|improve this answer

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106

$endgroup$

share|cite|improve this answer

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106

answered Jun 22 '12 at 14:12

nullUsernullUser

16.8k442106