Ten pink socks and ten purple socks are all mixed up in a drawer. The twenty socks are exactly alike except for colour. The room is pitch dark. How many socks do you need to take out to be sure you have a matching pair?
2007-02-05 16:03:28 · 14 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Three. If you take out only two, you MAY have a pair, or you may have one pink and one purple. When you take out the third sock, it has to be either pink or purple. If the first two made a pair, then it doesn't matter. If the first two didn't match, then you have one pink and one purple, and the third one HAS to match one of them.
2007-02-05 16:13:07 · answer #1 · answered by Anonymous · 0⤊ 0⤋
The answer is not three... because you can't distinguish colors. If you could distinguish colors, the answer would, in fact, be three. The key part in this question is the statement 'the room is pitch dark'.
The correct answer is, in fact, 11.
At the worst case, you'd pick out 1 pink/purple sock and then pick the rest of the opposite color, until you exhaust them.
So 1 color + 10 opposite color = 11 socks you'd need to take out to be sure you get a matching pair by picking the 12th sock.
2007-02-06 00:14:32 · answer #2 · answered by vaca loca 3 · 0⤊ 0⤋
Ans is 11
Since you have 10 purple and 10 pink socks.
There is a chance for tacking 10 pink or 10 purple socks id you drawn 10 socks. So 11 is right answer.
2007-02-06 00:12:08 · answer #3 · answered by Rhul s 2 · 1⤊ 0⤋
11
2007-02-06 00:05:57 · answer #4 · answered by pssstoast 1 · 1⤊ 0⤋
With my luck, 20. But the correct answer is 3 socks. One purple, one pink, and then it doesn't matter.
2007-02-06 00:06:34 · answer #5 · answered by Sweet n Sour 7 · 0⤊ 0⤋
To be sure you have a matching pair, you need to take out three socks.
2007-02-06 00:06:24 · answer #6 · answered by Yahoo! Answers 2 · 0⤊ 0⤋
You're British, aren't you?
3 socks
2007-02-06 00:05:50 · answer #7 · answered by OriginalSim 3 · 0⤊ 1⤋
Three.
They'll be either...
two pink and a purple
two purple and a pink
three pink
three purple
2007-02-06 00:05:10 · answer #8 · answered by odandme 6 · 0⤊ 0⤋
3, solved via common sense.
If there is only 2 color options, go with worst case scenario.
First two picks are one of each color, 3rd pick is the "match".
2007-02-06 00:05:39 · answer #9 · answered by csucdartgirl 7 · 1⤊ 0⤋
you need to take out three socks.
2007-02-06 00:06:25 · answer #10 · answered by Dancer101 4 · 0⤊ 0⤋