Search found 7 matches
Given data The frequency of each of the distinct alphabets in the word PROPORTION are: P = 2, R = 2, O = 3, T = 1, I = 1, N = 1 Total no. of alphabets with repetitions = 10 Total no. of distinct alphabets = 6 a) No. of ways to select 3 alike = 1 No. of ways to select 1 different from 5 distinct let...
- by Quasar Chunawala
Sat May 03, 2014 3:57 am- Forum: Problem Solving
- Topic: Permutaiton and Combination -Letter Problem
- Replies: 2
- Views: 1213
GmatGuruNY, For (A), in fact I deduced that No. of ways of (not selecting A and C together) = Total - (no. of ways to have both A and C) But, the answer caused doubt. You offered a very lucid explanation. And that C may be selected, even if A isn't. Nice catch! I wish I'd have spotted that. Gee than...
- by Quasar Chunawala
Sat May 03, 2014 3:34 am- Forum: Problem Solving
- Topic: Permutaion and Combination- Books arrangemnt
- Replies: 5
- Views: 1557
Probability = Favourable outcomes/Total outcomes
Think of (1,2,3) as one whole. That way, you have 7 items.
No. Of arrangements = 7!
Total no. Of arrangements = 9!
Probability = 7!/9! = 1/72.
- by Quasar Chunawala
Sat May 03, 2014 1:07 am- Forum: Problem Solving
- Topic: Probability
- Replies: 4
- Views: 3499
Combinations
B. No. of ways to select 5 out of 12 books(such that if A is selected, C also must be selected) (i) Suppose A is selected, then C is also selected. C(10,3) ways (ii) Suppose A is not selected, then C is also not selected. C(10,5) ways Total number of ways = C(10,3) + C(10,5) = 120 + 252 = 372 Not su...
- by Quasar Chunawala
Fri May 02, 2014 11:59 pm- Forum: Problem Solving
- Topic: Permutaion and Combination- Books arrangemnt
- Replies: 5
- Views: 1557
Strictly based on number theory learnt in GMAT alone , I don't know a quick way to check perfect squares. However, based two special number properties, here's a fast way to do it - 1. Perfect squares always end in 1,4,5,6,9 . Eliminate choices (C) and (E). 2. Digital roots of a perfect square are fr...
- by Quasar Chunawala
Fri May 02, 2014 11:15 pm- Forum: Problem Solving
- Topic: Which of the following numbers is a perfect square?
- Replies: 1
- Views: 6578
Problems where they'd ask what's the greatest or what's the least , in my mind, I apply a technique similar to this : The maximum number of pairs that could remain = 10 - Min(No. of Sock pairs lost) It's easy to imagine with 7 individual socks, you could form 3 pairs + 1 or 2 pairs + 3 or 1 pair + 5...
- by Quasar Chunawala
Thu Apr 17, 2014 5:57 am- Forum: Problem Solving
- Topic: Problem Solving - Doubt on question from OG11
- Replies: 10
- Views: 3855
The explanation above is extremely clear. It helps if you remember permutations and combinations from college-time. The number of ways of arranging r objects from a set of n items are http://s13.postimg.org/vq21u4khf/Permutations.png The number of ways of selecting r objects from n choices are http:...
- by Quasar Chunawala
Wed Apr 16, 2014 10:17 pm- Forum: Problem Solving
- Topic: no two ladies sit together?
- Replies: 9
- Views: 35707