Answer:
3 packages 
Explanation:
first we need to make this into a equation that we can solve!
x = 21/7
 if we use our times tables then we know that
7 * 3 
= 21 
so knowing what we know, lets go back to the question/ equation! 
21/7
= 3
( if you wanted, that could also be a way to double check you answer :)
hope this helped you and if you have any more questions then please ask me! :)