68 units to study and randomly give you 5 to choose 1

[eugenime]

68 units to study and they randomly give you 5 and you have to write only 1 of the 5. How many of the 68 do I have to study to have a good chance? 95% at least.

68/35/5=

Is this correct formula? 35 being the studied units.

 

[eugenime]

68 units to study and they randomly give you 5 and you have to write only 1 of the 5. How many of the 68 do I have to study to have a good chance? 95% at least.

68/35/5=

Is this correct formula? 35 being the studied units.

Sorry, I think 32/68/5*1000=94 makes more sense.
But I think there's something wrong because if you study 35 you have more than a 100% of getting one of your studied units?? This can't be right, can it?

 

[Deleted member 4993]

Sorry, I think 32/68/5*1000=94 makes more sense.
But I think there's something wrong because if you study 35 you have more than a 100% of getting one of your studied units?? This can't be right, can it?

If you study 64 units out of 68 -

and then pick a group of any 5 units out of 68​

​

- out of those 5, you would have studied at least 1 unit.​