Answer:
7 baseball cards
Step-by-step explanation:
Number of baseball cards = 45
Number of invited friends = 12
We are given that half of the friends were able to attend.
So, Number of friends attended the cookout = 
= 
Armando had 3 cards left for himself.
So, Number of cards distributed among 6 friends = 45-3 =42
So, number of cards for 6 friends = 42
So, number of cards for 1 friend = 
= 
Hence each friend receive 7 baseball cards.