Question 1123129
12 computers.
1 is missing a component.
the probability that a computer has a missing component is 1/12.


the first one he checks has that probability.


if the first one that is checked is ok (doesn't have the missing component), then there are 11 computers left, one of which has the missing component.


the probability of finding the missing component the next time a computer is picked is now 1/11.


why is it differnt?


because the computer with the missing component is still in the pile that hasn't been checked yet, but the pile is now 11 computers instead of 12.


that changes the probability of randomly picking the computer with the missing component from 1/12 to 1/11.