Answer:
The puppy weighed 6 pounds at birth.
Step-by-step explanation:
First, we can see that the puppy gains weight in a steady pace of 2.5 pounds every week :
4 weeks : 16 pounds
4x2.5 = 10 pounds
16 pounds - 10 pounds, because 0 weeks means starting at 0 years old. 16 - 10 = 6 pounds.
