Returning to competitive golf after surgery on his back, Tiger was seen
walking to the driving range carrying a shag bag.
In the bag were 24 Titleist golf balls, 24 Callaway golf balls, 24 Srixon
golf balls and 24 Nike golf balls.
Without looking at his balls, how many does Tiger have to remove from his
shag bag to guarantee a pair of similar balls?
Removing 5 golf balls guarantees a pair of similar balls.