Vocabulary in context: Motley (line 37): Although the KIPP students share similar economic and social circumstances, they have varying levels of ability and diverse academic backgrounds. Why is Gladwell's use of the word motley to describe these students crucial to understanding his point in this sentence?

describes a diverse background.

Explanation:

The use of the word "motley" describes something made of diverse colors to give a beautiful blended appearance. Here is an example:

In the sentence above, the motley shows that there are many colors involved on the single coat. Thus, the diverse background is synonymous with a motley.  

that is good that you know it

i'm not too sure - if you could attach the picture