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Class 11MathematicsPermutations and CombinationsFundamental principle of countingHard
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A locker system has (4) keys, (6) rooms, and (5) boxes. The first key opens only (3) boxes, while the other (3) keys open all (5) boxes. How many valid selections are possible?

Answer and explanation

Correct answer: (108)

Rooms are independent and key-box choices are (1\times3+3\times5=18), so (6\times18=108). Count dependent choices together.

Related tags

Permutations-And-CombinationsFundamental-PrincipleCountingHardFundamental Principle Of CountingPermutations And CombinationsMathematicsClass 11 Mcq
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