Answer: at lease 8 packages of Aero flight tees.
Explanation:
At least 10 golf tees for each member of his foursome = total of at least 4*10 = 40 tees.
2 packages of the generic golf tees, that are packaged by the dozen = 2*12 = 24 tees.
So, Bill must buy at least 16 Aero tees.
This means he must buy 8 pairs