[<< wikibooks] A Guide to the GRE/Ratios
```= Ratios =
A ratio express the proportion of two commodities in relation to each other (as opposed to in relation to the whole, as a fraction or percentage does).

== Rules ==
Add both numbers in a ratio to get the total amount with respect to each.
A ratio expresses quantity in relation to the other.  This is not to be mixed up with parts of the whole.  If the ratio of Democrats to Republicans at a conference is 6 to 4, then Republicans make up 40% of the conference (4 divided by 6 + 4).  If guitar players make up 70% of the rock band seminar and drummers make up 30%, then the ratio of guitarists to drummers is 7 to 3.

== Practice ==
1.  Of the 50 lawyers at the meeting, 22 are bankruptcy lawyers; the remainder are divorce lawyers.  What is the ratio of bankruptcy lawyers to divorce lawyers?
2.  The ratio of stocks to bonds in the portfolio is 4 to 9.  If there are 169 items in the portfolio, how many of them are bonds?
3.  The ratio of ratio questions to non-ratio questions on the math quiz is 4 to 5.  If there are a total of 36 questions, how many are ratio questions?