Mental Math The ratio of
girls
to
boys
at a movie is
8 : 3.
If there are
9
boys,
how many
are at the movie?
There are
at the movie.
3/11 are boys
So
(3/11) * ( total number) = 9
total number = 9 ( (11/3) = 33
33 - 9 = 24 are girls
3 : 9 = 8 : x
3x = 72
x = 24
+132 
