Question 1123129: After assembling an order for 12 computer systems, the assembler noticed that an electronic component that was to have been installed was left over. The assembler then checked the 12 systems in order to find the system missing the component. Assume that he checks them in a random order.
(a) What is the probability that the first system the assembler checks is the system that is missing the component?
(b) What is the probability that the second system the assembler checks is missing the component, assuming that the first system he checked was OK?
(c) Explain why the answers to parts (a) and (b) are different.
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! 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.
|
|
|
