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Two engineers go to a job interview. They are introduced and told they are looking for people with team working skills. Without time to talk or get to know each other, they are guided to two different rooms with a window from which they see a wind turbine park.
Engineer A can see 22 turbines.
Engineer B can see 4 turbines.
They are told that in the park there are 24 or 26 turbines, none of them are seen by both engineers at the same time, and between the two they can see all the turbines in the park.
During the next hours, an interviewer will ask them a question per round, always being the same question. He will ask first to engineer A, and, if he does not answer, will then ask to engineer B. The question is: "Are there 24, or 26 turbines in the park?".
If one of the engineers answer correctly, both are hired.
If one answer incorrectly, none will be hired.
If there's no answer, the interviewer will go ask the next engineer, starting a round of "question to engineer A - question to engineer B", always starting by engineer A.
Knowing that both consider they are very logic people and really want the job: In how many rounds will they manage to answer correctly, without any doubt, if possible?
EDIT: Oras found this puzzle asked 2 years ago (with a different story) here, however since the numbers differ and it's rather old I will keep the post. By the way, this is my first post here, glad to be part of the community!