Question

If $ {{N}_{a}}=\{an:n\in N\}, $ then $ {{N}_{5}}\cap {{N}_{7}} $ is equal to:

• A. $ {{N}_{7}} $
• B. $ N $
• C. $ {{N}_{35}} $
• D. $ {{N}_{5}} $
• E. $ {{N}_{12}} $

Answer 1

Answer: (C)

$ \because $ $ {{N}_{5}}=(5,10,15,20,25,30,35,...) $
and $ {{N}_{7}}=\{7,14,21,35,...\} $
$ \therefore $ $ {{N}_{5}}\cap {{N}_{7}}=\{35,70,.....\}={{N}_{35}} $