GRE
Exam
Numerical Ability
Permutation and Combination
Martha invited 4 friends to go with her to the movies. There are 120 different
ways in which they can sit together in a row. In how many of those ways is
Martha sitting in the middle?
Read Solution (Total 5)
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- There are total 120 ways as given in qn.
Out of total 5 persons, everyone will come in middle for same number of times.
so Martha will sit in middle for 120/5 =24 ways - 15 years agoHelpfull: Yes(1) No(1)
- 24...as 1st place can be occupied by any of the 4friends(as martha in the middle) 2nd place can be occupied by any of the remaining 3...
middle only 1 way...as only martha will
4th place in 2 ways and the lastplace in 1 way..
hence 4*3*1*2*1=24 - 12 years agoHelpfull: Yes(1) No(0)
- 4! = 24 ways.
In-fact, there are 24 ways each in which Martha sits in 1st, 2nd 3rd, 4th and 5th positions. If you consider only the middle position (3rd position), it is 24. - 15 years agoHelpfull: Yes(0) No(0)
- 24
- 15 years agoHelpfull: Yes(0) No(1)
- Fix the martha position in middle there are remaining 4 posions. we can arrange them in 4! ways (i.e., 24)
- 11 years agoHelpfull: Yes(0) No(0)
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