As long as the blue ball hits, the red ball hits less than three (excluding three).

The calculation process is as follows

1/ 16* 1/(6*5+6+ 1)

116 is the probability that you win the blue ball, and 1/(6*5+6+ 1) is the probability that you win the red ball less than three (excluding three).

It should be like this.

I almost forgot math. Don't blame me for my mistake.