Recent questions tagged pigeonhole-principle

5 votes
2 answers
91
How many number must be chosen from site {1 2 3 4 5 6 7 8 }such that at least two of them must have sum equal to 9?A.28B.9C.5D.10
0 votes
0 answers
92
During a month with 30 days, a baseball team plays at least one game a day, but no morethan 45 games. Show that there must be a period of some number of consecutive days ...
1 votes
3 answers
94
18 votes
1 answer
97
5 integers randomly chosen from 1 to 2015. What is the probability that there is a pair of integers whose difference is a multiple of 4?
4 votes
2 answers
100
2 votes
1 answer
101
The numbers $1, 2, \dots , 10$ are arranged in a circle in some order. Show that it is always possible to find three adjacent numbers whose sum is at least $17$, irrespec...
1 votes
1 answer
102
A group of $15$ boys plucked a total of $100$ apples. Prove that two of those boys plucked the same number of apples.
3 votes
1 answer
103
Prove that in any sequence of $105$ integers, there will always be a subsequence of consecutive elements in the sequence, whose sum is divisible by $99$.
1 votes
1 answer
104
0 votes
0 answers
106
The least num of computers required to connect 8 computers to 4 printers to guarantee 4 comp can direct]ly access 4 printer is _____1617192021
1 votes
1 answer
107
There exists a set $A \subset \left\{1, 2,....,100\right\}$ with $65$ elements, such that $65$ cannot be expressed as a sum of two elements in $A$.
2 votes
2 answers
109
Prove that at a party where there are at least two people, there are two people who know the same number of other people there.
0 votes
1 answer
110
Show that there are at least six people in California (population: 37 million) with the same three initials who were born on the same day of the year (but not necessarily...
1 votes
1 answer
111
Show that in a group of 10 people (where any two people are either friends or enemies), there are either three mutual friends or four mutual enemies, and there are either...
0 votes
1 answer
112
Show that in a group of five people (where any two people are either friends or enemies), there are not necessarily three mutual friends or three mutual enemies.
1 votes
1 answer
113
Assume that in a group of six people, each pair of individuals consists of two friends or two enemies. Show that there are either three mutual friends or three mutual ene...
8 votes
1 answer
114
During a month with 30 days, a baseball team plays at least one game a day, but no more than 45 games. Show that there must be a period of some number of consecutive days...
60 votes
9 answers
115
39 votes
6 answers
116
The minimum number of cards to be dealt from an arbitrarily shuffled deck of $52$ cards to guarantee that three cards are from same suit is$3$$8$$9$$12$