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Joined: 20 Feb 2017
Posts: 2506
Given Kudos: 1055
GPA: 3.39
In how many ways can a four-letter password be chosen, using the
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11 Jul 2021, 23:25
11 Jul 2021, 23:25
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In how many ways can a four-letter password be chosen, using the letters A, B, C, D, E, and/or F, such that at least one letter is repeated within the password?
A. 720
B. 864
C. 900
D. 936
E. 1,296
A. 720
B. 864
C. 900
D. 936
E. 1,296
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Joined: 16 Apr 2020
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Posts: 1546
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In how many ways can a four-letter password be chosen, using the
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13 Jul 2021, 21:35
13 Jul 2021, 21:35
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GeminiHeat wrote:
In how many ways can a four-letter password be chosen, using the letters A, B, C, D, E, and/or F, such that at least one letter is repeated within the password?
A. 720
B. 864
C. 900
D. 936
E. 1,296
A. 720
B. 864
C. 900
D. 936
E. 1,296
Total number of ways = \((6)(6)(6)(6) = 1296\)
Number of ways in which no letter repeats = \((6)(5)(4)(3) = 360\)
Number of possible passwords where at-least 1 alphabet is repeated = \(1296 - 360 = 936\)
Hence, option D
gmatclubot
In how many ways can a four-letter password be chosen, using the [#permalink]
13 Jul 2021, 21:35
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