My remote control needs two new batteries, but when I went to get replacements I found that the four good batteries got mixed in with four bad batteries. The only means of determining if the batteries are good is to put two into the remote and see if it works. The remote works with two good batteries and is unresponsive if I have at least one bad battery in it.
What is the minimum number of tries I need to guarantee that I get two good batteries?
(In reply to my solution
Apparently, I've answered a wrong question ( trying the batteries two-by-two what is the worst case?) and failed address the real issue.
Your approach is a correct one , but the answer( to puzzle's questi
i.e. What is the minimum number of tries I need to guarantee...etc is 7 , not eight : you were requested to identify a pair of good batteries, not to immediately use them.
PS I - THere is a typo in the title - don't know how to edit it...
PS II- Meanwhile I have posted a shorter procedure.
Edited on November 12, 2013, 4:23 am