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There are 10 lamps in a hall. Each one of them can be switched on independently.Find the number of ways in which the hall can be illuminated.(A)102(B)1023(C)2610(D)10! |
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Answer» Given : Total number of lamps =10 Since at least one lamp is to be kept switched on The total number of ways are 10C1+10C2+....10C10 ⇒210−1 ⇒1024−1 ⇒1023 Hence (B) is the correct answer. |
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