All I can remember is to work out $6!$ then deal with the last term which can only be A or O but I do not know what to do!
Can anyone please show me with workings and terminology?
Thanks in advance!
All I can remember is to work out $6!$ then deal with the last term which can only be A or O but I do not know what to do!
Can anyone please show me with workings and terminology?
Thanks in advance!
It's easier to first deal with the last placeholder, then the first 5 placeholders. The last placeholder can only be "A" or "O", so that gives 2 choices. And there are $5!$ permutations for the first 5 placeholders. So there are $5!\times 2 = 240$ arrangements in total.