I have been using the free online resource Elementary Introduction to the Wolfram Language for a number of years to introduce beginning biologists to the Wolfram Language. The text is a great resource, yet every year we get to Question 7.9 in Chapter 7, and my students (and me) get frustrated that the expected output does not match the output created by the answer keys own proposed solution.
See this screenshot: 
The only workaround I know of - and which I share with students - is to use a Graphics statement.
Is the problem with this question that the expected output is wrong OR should Style[Purple,100] produce the correct output but doesn't?