Search found 26 matches
Consider the 3 Americans and 2 Canadian as a single entity as they always are together. So we have the following pattern ACI which can be arranged in (3!) ways = 6 ways. Further the 3 Americans and 2 Canadians can be arranged in 3! and 2! ways among/between them. So required no of arrangements = 6 *...
- by smanstar
Tue Sep 25, 2012 9:12 pm- Forum: Problem Solving
- Topic: permutations and combinations
- Replies: 4
- Views: 11059
Total no of ways of selecting 3 people from a group of 8 people = 8C3 ways = 56 ways
number of ways in which the two twins are from same group is 4 * 6C1 = 24 ways
so no of ways in which the two twins NOT from same group ( 56- 24) = 32 ways
- by smanstar
Tue Sep 25, 2012 9:05 pm- Forum: Problem Solving
- Topic: combinations
- Replies: 10
- Views: 5391
probability of red and ace ???
Q
Two cards are drawn from a pack of card , find the probability that 1st card is red and the second is an Ace, when the 1st card is.
a) Replaced ?
b) not Replaced?
- by smanstar
Tue Sep 25, 2012 8:50 pm- Forum: Problem Solving
- Topic: probability of red and ace ???
- Replies: 4
- Views: 1695
Gmat teaser
In how many ways can you distribute 30 identical balls in 7 boxes (B1, B2..., B7)
Such that :
No 2 boxes have same no of balls and at-least 1 ball is in each box ? [/quote]
- by smanstar
Tue Sep 25, 2012 8:40 pm- Forum: Problem Solving
- Topic: Gmat teaser
- Replies: 3
- Views: 1476
Q In how many ways can 5 letters be posted in 4 mail boxes , any letter can be posted in any mail box ?? How i tried to solve 5 letters each letter has 4 choices so 4*4*4*4*4 = 4^5 ways but I get confused, when I tried to solve the same in this way 4 mail boxes each can accept 5 letters so 5*5*5*5 ...
- by smanstar
Tue Sep 11, 2012 1:54 am- Forum: Problem Solving
- Topic: a basic combination -- help needed
- Replies: 3
- Views: 1307
a basic combination -- help needed
Q In how many ways can 5 letters be posted in 4 mail boxes , any letter can be posted in any mail box ?? How i tried to solve 5 letters each letter has 4 choices so 4*4*4*4*4 = 4^5 ways but I get confused, when I tried to solve the same in this way 4 mail boxes each can accept 5 letters so 5*5*5*5 =...
- by smanstar
Tue Sep 11, 2012 12:59 am- Forum: Problem Solving
- Topic: a basic combination -- help needed
- Replies: 3
- Views: 1307
in how many ways can 3 couples sit in a circular table such that no pair of husband wife are opposite to each other ? 1) 60 2) 100 3)64 4) 96 Let the 3 couples be A and B, C and D, E and F. With circular arrangements, where the FIRST person sits is IRRELEVANT. All that matters is the number of ways...
- by smanstar
Mon Sep 10, 2012 8:17 pm- Forum: Problem Solving
- Topic: circular arrangement
- Replies: 3
- Views: 5935
circular arrangement
in how many ways can 3 couples sit in a circular table such that no pair of husband wife are opposite to each other ?
1) 60
2) 100
3)64
4) 96
- by smanstar
Mon Sep 10, 2012 9:36 am- Forum: Problem Solving
- Topic: circular arrangement
- Replies: 3
- Views: 5935
Q In how many ways can 5 letters go into 5 envelopes such that: 1. No letter goes into its corresponding envelope? A DERANGEMENT is a permutation in which NO element is in the correct position. Given n elements (where n>1): Number of derangements = n! (1/2! - 1/3! + 1/4! + ... + ((-1)^n)/n!) Given ...
- by smanstar
Mon Sep 10, 2012 4:27 am- Forum: Problem Solving
- Topic: permutation : Envelopes and letters
- Replies: 6
- Views: 31057
Where are the answer choices? Anyways, it could be as follow: 5 letters can go into 5 envelopes in 5! ways, i.e. 5! = 120, and there is just 1 combination in which each and every letter goes to its corresponding envelope, thus 120-1=119 for first condition 1 letter in its correct corresponding enve...
- by smanstar
Mon Sep 10, 2012 3:01 am- Forum: Problem Solving
- Topic: permutation : Envelopes and letters
- Replies: 6
- Views: 31057
permutation : Envelopes and letters
Q
In how many ways can 5 letters go into 5 envelopes such that:
1. No letter goes into its corresponding envelope?
2. Exactly 1 letter goes into its corresponding envelope?
- by smanstar
Mon Sep 10, 2012 2:29 am- Forum: Problem Solving
- Topic: permutation : Envelopes and letters
- Replies: 6
- Views: 31057