A sample of 50 11th graders were asked to select a favorite pattern out of 6
choices. The data list below shows what their favorite color patterns were,
and the accompanying frequency table and bar graph represent these data. In
the bar graph, the height of the blue-gray bar is 4, the height of the green bar
is 9, and so on.

Suppose that, rather than being just a bar graph, the display you see above is
a relative frequency bar graph. The vertical axis of the graph will be marked
off in percentages, from 0 percent up to 30 percent. What will be the height of
the GREEN bar?