# How many earrings do you have to pick up? [closed]

I'm having trouble solving a puzzle in Swedish. I've translated it below:

1. How many earrings do you have to pick up to be sure to get a pair of the same in a mix of earrings where "favorable outcomes" represent 4/20 from the start. This was not a probability calculation to be performed because logical thinking gives that you have to pick up all the remaining sixteen to know that no error possibilities remain. So you have to pick up 18 to be sure to get the pair in your hand.

I'm not sure where to begin with this puzzle. How do I calculate the number of earrings that need to be picked up to ensure that I get a pair of the same type?

Here is the origin of the puzzle: https://cdn.discordapp.com/attachments/869145673197580298/1083855309942030346/PIL_-_sammanfattning_av_fragor_oscar_bakhouch.doc

• As is the case with many of your recent posts, the question you've asked here may be puzzling to you, but that does not make it a puzzle. This is a fairly basic math/probability problem one might find in a textbook; such questions are off-topic here, as there is no real puzzling element to be solved. Please take some time to look around and familiarize yourself with the kinds of questions that are well-received here, ideally before you post any more questions.
– Rubio
Mar 12, 2023 at 15:44