If \( \Large N_{a}=\{ an : n \epsilon N \} \), then \( \Large N_{3} \cap N_{4} \) is equal to:

A) \( \Large N_{7} \)

B) \( \Large N_{12} \)

C) \( \Large N_{3} \)

D) \( \Large N_{4} \)

Correct answer:
B) \( \Large N_{12} \)

Description for Correct answer:
Given that \( \Large N_{a}=\{ an:n \epsilon N \} \)

\( \Large N_{3} \cap N_{4} = \{ 3,\ 6,\ 9.\ 12,\ 15, ..... \} \cap \{ 4,\ 8,\ 12,\ 16,\ 20, ... \} \)

= \( \Large \{ 12,\ 24,\ 36, ... \} = N_{12} \)


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