Answer:
Considering the set:
[tex]A=\{ 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, \\35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46 \}[/tex]
In order to find the numbers that are not multiples of 2, eliminate the even.
[tex]B=\{ 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45 \}[/tex]
Now eliminate the multiples of 7.
[tex]C=\{ 23, 25, 27, 29, 31, 33, 37, 39, 41, 43, 45 \}[/tex]
So, you got the 11 numbers.
Note: The multiples of both 2 and 7, are 28 and 42.