Someone please explain

Answer:
D) 6
Step-by-step explanation:
set Q has 16 values which are all even values from 4 to 36
set Z has 11 values that are multiples of 3 from 4 to 36 (6,9,12,15,etc.) however, we have to eliminate the odd ones, leaving the following six:
6, 12, 18, 24, 30, 36
Answer:
D. 6
Step-by-step explanation:
Key skills needed: Set Similarity
1) The easiest way to teach this is by writing out each set, but I will show it to you in 2 ways.
2) The first way is by writing everything out.
Set Q = 4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36
Set Z = 3,6,9,12,15,18,21,24,27,30,33,36
(I only wrote out Set Z to 36 since Set Q ends at 36. Anything greater than 36 won't even be there in Set Q, so no point in writing more.
3) The next way is with using a simple pattern.
Set Q contains all even numbers from 4 to 36
Set Z contains all multiples of 3 (no limits)
Therefore, the numbers that are in both sets would be:
The even multiples of 3 that are bigger than 4 and less than 36.
4) Those even multiples of 3 would be ---> 6,12,18,24,30,36
Both show that D is the answer, so I would say D as the answer very confidently.
Hope you understood and have a nice day!! :D