Socks

Probability Level 1

Allie has a drawer with several pairs of white socks and yellow socks.

One early morning, the bulb burned out and Allie needed to pick her socks in the dark.

What is the minimum number of socks (the color doesn't matter) that she should pick to make sure she gets at least one pair (two socks of same color)?

Image credit: Flick Dwight Sipler . Image cropped
2 3 4 5

Victor Paes Plinio by Victor Paes Plinio , 21, Brazil

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

4 solutions

Nguyen Thanh Long
Oct 22, 2014

Because if pick two socks, it may have three possibilities: i) two are white; ii) two are yellow; iii) one is white, one is yellow. So in all these cases, add one sock to get one pair of sock. a n s = 3 ans = \boxed{3}

2 Helpful 0 Interesting 0 Brilliant 0 Confused

Several is more than three but less than many so to make sure you would have to pick at least five

Larry Hanks - 6 years, 7 months ago

Log in to reply

5+3+2=151022, 9+2+4=183652, 8+6+3=482466, 5+4+5=202541, 7+2+5=?

Sagar Rajput - 6 years, 2 months ago

There are only two colors of socks, white and yellow. It means that the first two picks is yellow and white (in any order). Then the third pick will give her a pair (yellow or white).

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Anshul Sanghi
Jul 11, 2016

I would suggst the answer 3 is wrong.You asked minimum ,3 is maximum.answer should be 2 or else specify according to probability...

0 Helpful 0 Interesting 0 Brilliant 0 Confused

You must 'make sure' that she gets at least two socks of same color.

If you pick two socks, you might get two different colors of socks.You are just testing your luck.

Ong Zi Qian - 3 years, 7 months ago
Xander Long
Oct 23, 2014

Since there are only two possible colors, you just need to grab 3, because you are then garunteed at least two of any color. With two socks, you either have 2 white, 2 yellow, or one of each, for all of these cases, a sock of any color would give you a pair

0 Helpful 0 Interesting 0 Brilliant 0 Confused

since the pair of socks allie has in her drawer is not mentioned, any number of socks taken out could be of same colour.

Meera Shivaram - 6 years, 7 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...