The Gateway to Computer Science Excellence
+1 vote
1.4k views

How many cards must be chosen from a deck to guarantee that at least

  1. two aces of two kinds are chosen.
  2. two aces are chosen.
  3. two cards of the same kind are chosen.
  4. two cards of two different kinds are chosen.
  1. $50, 50, 14, 5$ 
  2. $51, 51, 15, 7$ 
  3. $52, 52, 14, 5$ 
  4. $51, 51, 14, 5$ 
in Combinatory by Boss (29.9k points)
retagged by | 1.4k views

1 Answer

+2 votes

since we have to be sure (  guarantee) consider the worst cases for all 

i)two aces of same kind are chosen  (first 48 cards without ace 49th will surely be  an ace and  50 th will be of another ace) Here kind word is incorrectly given

ii) two aces are chosen   first 48 cards can be  without ace then 49th and 50th will definitely be ace

iii)two cards of same kind that  is same number so first 13 can be of different numbers but  14 th will definitely match with someone

iv)2 cards of 2 different kinds   let first 4 are of same number  say all ace or all 2 etc now 5th one will be definitely different number  

So ans is A  50 50 14 5

 

Note :- kind means number here so option A language is not proper

by Boss (48.6k points)
edited by
Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
50,666 questions
56,167 answers
193,833 comments
93,990 users