Respuesta :

Code:

num = 3

while num <= 21:

   print(num)

   num+=3

Output of code:

3

6

9

12

15

18

21

Explanation:

The condition num <= 21 will ensure that the program will only print multiples of 3 up to 21. We set num as 3 since we want to start printing from 3, and we add 3 each time to get the multiples.

Hope this helps :)