Hello,Originally Posted by Navesh
you've got exactly 5 places where you can put a bead.
For the first red bead you can choice out of 5 places, for the second red bead there are only 4 places left. Similar to the two yellow beads and the blue on:
That means you've got 5*4*3*2*1 = 120 possibilities. BUT : Because you can't distinguish between the first or the second red bead, and you you can't distinguish between the first or the second yellow bead, the amount of possibilities is 4 times to great. So finally: