*sniff* *sniff* you saying I don't explain good!!!! LoLOr to simplify the above for those that still don't get it.
Let's start with two of the three 8 ohm speakers, then do this:
8x8=64, 8+8=16. Now divide 64 by 16. It should equal 4
Now take that 4 and do the same thing with the remaining 8 ohm speaker.
4x8=32. 4+8=12. 32 divided by 12 = 2.6666666666667
Exactly how I do the calculation in my head. Easy when the resistance of each of the resistors is the same.I must have a simple mind.
If all the parallel resistances are the same, simply divide one resistor's resistance by the total number of resistors. Or in your case 8/3 as already posted.
If the any of the resistances are different, take the inverse of each resistor's resistance and sum (add) them up. Then take the inverse of the answer.
In your case with 8 ohm resistors:
So 1/8 + 1/8 + 1/8 = 0.375
Then take the inverse of that for the parallel resistance:
1/0.375 = 2.67