Question

If C = {integers divisible by 6 from 1 to 30} and D = {integers divisible by 3 from 1 to 20}, what is C ∩ D?

{3, 6, 9, 12, 15, 18, 24, 30}

{6, 12, 18, 24, 30}

{6, 12, 18}

{ }

Answer 1

CnD is the set of elements that C and D have in common

Answer 2

Also, it would help to list the elements of each set:
\[C=\left\{6,12,18,24,30\right\}\\
D=\left\{3,6,9,12,15,18\right\}\]