Hello, Mhmh96!

If someone have 4 red bricks and 8 blue bricks and arranges them randomly in a circle,

what is the probability that two red bricks areside by side?not

There are possible arrangements.

(This includesduplication from rotations.)

Place the 8 blue bricks in a circle, leaving a space between them.

. .

Select 4 of the 8 spaces and insert the red bricks.

There are: ways.

Therefore: .