Determine the number of colors needed to label $V(K_n)$ such that each color class induces a subgraph with maximum degree at most $k$.
I'm not sure what this problem is even asking. I know that the complete graph of order $n$ has $n$ different color classes since every vertex is adjacent to every other vertex. Also, induced subgraphs of $K_n$ are also complete graphs of equal or smaller order. What is this problem asking me to do? I am lost. Any hints or solutions are greatly appreciated.
HINT:
In this problem you are not asked for a "proper" coloring. This means that it is allowed for adjacent vertices to have the same color.
Now an induced subgraph of a complete graph is itself a complete graph. This means that maximum degree at most $k$ implies that such a subgraph can have at most $k+1$ vertices.
Can you finish it by yourself?