If p is a prime number greater than 3, then (p2 - 1) is always divisible by :
A. 6 but not 12
B. 12 but not 24
C. 24
D. None of these
Answer: Option C
Solution (By Examveda Team)
⇔ p = 5⇒ (p2 - 1) = (25 - 1)
⇒ (p2 - 1) = 24, which is divisible by 24
⇔ p = 7
⇒ (p2 - 1) = (49 - 1)
⇒ (p2 - 1) = 48, which is divisible by 24
⇔ p = 11
⇒ (p2 - 1) = (121 - 1)
⇒ (p2 - 1) = 120, which is divisible by 24
Hence, (p2 - 1) is always divisible by 24
This Question Belongs to Arithmetic Ability >> Number System
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