Final answer:
The 4-pack is the better value as each light bulb costs less compared to the 3-pack.
Step-by-step explanation:
To determine which pack is the better value, we can calculate the cost per light bulb in each pack.
In the 3-pack, each light bulb costs $3.45/3 = $1.15.
In the 4-pack, each light bulb costs $4.20/4 = $1.05.
Therefore, the 4-pack is the better value as each light bulb costs less compared to the 3-pack.