The GMAT Sample Math question for the day is from the topic Permutation and Combination on rearranging letters of a word.
In how many ways can the letters of the word "PROBLEM" be rearranged to make 7 letter words such that none of the letters repeat?
- 7!
- 7C7
- 77
- 49
- None of these
The correct choice is (A) and the correct answer is
7!.
There are seven positions to be filled.
The first position can be filled using any of the 7 letters contained in PROBLEM.
The second position can be filled by the remaining 6 letters as the letters should not repeat.
The third position can be filled by the remaining 5 letters only and so on.
Therefore, the total number of ways of rearranging the 7 letter word = 7*6*5*4*3*2*1 = 7! Ways.
eBooks on Permutation Combination & Probability
This ebook with over 110 questions in about 100 pages covers all major concepts in Permutation combination (combinatorics) and Probability. Includes typical GMAT like problems such as "tossing of coins", "rolling of dice" and "selecting cards from a pack of cards" 
This eBook is a practice test comprising 95 questions on Permutation, Combination and Probability. These questions are objective type multiple choice questions. Each question is provided with correct answers and detailed explanations at the end of the test. 
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