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Let p be a prime number such that 3 lt p...

Let p be a prime number such that `3 lt p lt 50`, then `p^2-1` is:

A

always divisible by 8

B

always divisible by 24

C

always divisible by 12

D

all of a, b, c

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The correct Answer is:
To solve the problem, we need to find the value of \( p^2 - 1 \) where \( p \) is a prime number such that \( 3 < p < 50 \). ### Step-by-Step Solution: 1. **Identify the Range of Prime Numbers**: We need to find all prime numbers \( p \) such that \( 3 < p < 50 \). The prime numbers in this range are: - 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47 2. **Calculate \( p^2 - 1 \) for Each Prime**: We will calculate \( p^2 - 1 \) for each of the identified prime numbers: - For \( p = 5 \): \[ p^2 - 1 = 5^2 - 1 = 25 - 1 = 24 \] - For \( p = 7 \): \[ p^2 - 1 = 7^2 - 1 = 49 - 1 = 48 \] - For \( p = 11 \): \[ p^2 - 1 = 11^2 - 1 = 121 - 1 = 120 \] - For \( p = 13 \): \[ p^2 - 1 = 13^2 - 1 = 169 - 1 = 168 \] - For \( p = 17 \): \[ p^2 - 1 = 17^2 - 1 = 289 - 1 = 288 \] - For \( p = 19 \): \[ p^2 - 1 = 19^2 - 1 = 361 - 1 = 360 \] - For \( p = 23 \): \[ p^2 - 1 = 23^2 - 1 = 529 - 1 = 528 \] - For \( p = 29 \): \[ p^2 - 1 = 29^2 - 1 = 841 - 1 = 840 \] - For \( p = 31 \): \[ p^2 - 1 = 31^2 - 1 = 961 - 1 = 960 \] - For \( p = 37 \): \[ p^2 - 1 = 37^2 - 1 = 1369 - 1 = 1368 \] - For \( p = 41 \): \[ p^2 - 1 = 41^2 - 1 = 1681 - 1 = 1680 \] - For \( p = 43 \): \[ p^2 - 1 = 43^2 - 1 = 1849 - 1 = 1848 \] - For \( p = 47 \): \[ p^2 - 1 = 47^2 - 1 = 2209 - 1 = 2208 \] 3. **Identify Common Factors**: Now we observe the results: - \( 24, 48, 120, 168, 288, 360, 528, 840, 960, 1368, 1680, 1848, 2208 \) We can see that all these numbers are divisible by 24. 4. **Conclusion**: Therefore, \( p^2 - 1 \) for any prime number \( p \) in the specified range will always be divisible by 24. ### Final Answer: The value of \( p^2 - 1 \) is always divisible by 24.
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