This question asked in june 2005 paper in UGC NET

Question 5:

Minimum number of individual shoes to be picked up from a dark room (containing 10 pair of shoes) if we have to get atleast one proper pair:

Answer:

firstly, write given data Which is present in the question.

In question, we have to picked atleast one proper pair.

 we have 10 pairs of shoes means 10 x 2 = 20 shoes.

If i will start one by one. when i will get atleast one pair.

Now think once, if you will choose 10 shoes and all shoes have no match with any shoe but when you will pick 11 shoe, it will definately the pair of any other shoe.

So the answer is 11