Colour Problem

[Dee-M-See]

If I had 25 Hankies divided equally into 5 colours and neatly stacked in a drawer
If I was then blinfolded how many Hankies would I have to take out to be sure of having one of each colour

[Dinkypuzzled]

17

[amalgam]

21? But then I am no good at this sort of puzzle!

[Aquariel]

If you're picking them at random, then the only way to be absolutely sure you have one of each colour would be to take 21 - if you take out 20 hankies you could in theory get all 5 hankies of 4 colours and none of the 5th colour.

At least it made sense to me - I'm sure somebody has a cleverer answer ...

i.e. if they are already stacked neatly in piles of colour, then you should be able to just take one from each pile :-)

[Dinkypuzzled]

Yes, of course - 21.

[Dee-M-See]

I have since been told the correct answer is 21
But thank you for your answers

[amalgam]

Surely, if you drew out 20 you might get, say 5 blue, 5 yellow, 5 red, and 5 green, but no brown, because the 5 brown would still be in the drawer? Dimmer and dimmer!

[grasscarp]

What I dont like about the question is the "neatly stacked in a drawer". If they were all higgledy piggledy the answer would be the same.......

[johnalex]

Interestingly, to guarantee 5 of one colour the answer would still the same, ie 21. This is based on the same possibility, 4A 4B 4C 4D 4E = 20, with the next hanky guaranteeing a set of 5.

. . . . I have just turned into a pumpkin! night night, ja

[blessedwith3]

4

[blessedwith3]

if they were divided equally (stacks of 5) subtracting the one already wearing you would simply go along the line taking one away from each pile of 5

Or is that answer too simple??
Now I am doubting the simplicity of it
nooooooooooooooooooo!!!!!!!!!!!!!!!!!!!!!

[*Princess*]

blessedwith3 - I LOVE your lateral thinking - thinking outside the box! Shows creativity and intelligence :o) Nice one!