How Many Times Do A Clock’s Hands Overlap In A Day?

Some interview questions seemingly come completely out of left field. A good example of this is the question: "How many times do a clock's hands overlap in a day?" The exact answer is not what the interviewer is necessarily looking for. Instead, hiring managers are looking to see if you are able to work out problems and come up with a reasonable solution.

At first, it might be tempting to just say "24," but the correct answer is "22." This can be surmised because the clock hands approximately overlap at 12:00, 1:05, 2:10, 3:15, 4:20, 5:25, 6:30, 7:35, 8:40, 9:45 and 10:50 twice a day. You will notice that there is no 11:55 because the hands will not overlap at that point because the hour hand is moving toward 12 when the minute hand is at 11.

Points to Emphasize

This is a bit of an oddball question, but if you are asked it, then you should bring up these points.

• Feel free to ask for a moment to think it through.
• Talk through your thought process.
• The correct answer is 22, but if you don't arrive at that answer, that's fine.
• See if there is a clock in the room for guidance.

If you can reach the right answer, then that is great. However, it is more important to show that you are capable of thinking through problems and reaching a reasonable conclusion.

Mistakes You Should Avoid

Although reaching the wrong answer is fine to an extent, you should avoid these common errors.

• Don't just blurt out an answer without thinking it through.
• If you give the wrong answer, don't get flustered.
• Don't say, "I don't know."
• Don't sit in silence.

If you just sit in your chair quietly, then the interviewer is not going to know how you came to your answer. Talking the answer out gives the hiring manager valuable insight into how you are able to think.

Sample Answer

Answering a brain teaser should go something like this:

Let me think about this for a moment. I want to say 24, but I feel like the answer is more complex than that. Let's see…the hands overlap exactly at noon and midnight, so that's two right there. They're not exact, but the hands would also overlap near 1:05, 2:10, 3:15, 4:20, 5:25, 6:30, 7:35, 8:40, 9:45, 10:50 and 11:55 twice each day. Actually, you know what, the hands wouldn't overlap at 11:55 since the hour hand is slowly moving toward 12. That means the hands overlap 22 times a day.

Giving an impulse answer is not good in this case. You want to show that you are capable of thinking a problem through thoroughly.