There are four balls of different colours and four boxes of the same colour . THe balls have to be put in the boxes of matching colours . Find the probability that all the four balls are not put in the right box .
Now figure out how many different ways there are altogether of putting the balls into the boxes, one in each. There are 4 ways of putting a ball into the first box, 3 ways for the second, and so on. So how many arrangements are possible altogether? Only one of these is correct. So what's the probability of that? So what's the probability that it's not correct?
If all four balls are not put in the right box, I understand that as meaning that all four balls are put in a wrong box. That's a derangement. Have you interpreted it as all four balls are not put in the right box therefore only some or none have been in the right box ....?Originally Posted by Grandad
(This is what I hate about these sorts of problems - for me I often find ambiguity in the wording .....)
Hello Mr F