1. **State the problem:** We need to find the expected adult weight of Britney's golden retriever puppy. 2. **Given information:** The expected adult weight is given by the formula $$\text{Adult weight} = 1.5w$$ where $w$ is the puppy's weight at 6 months. 3. **Substitute the given value:** Britney's puppy weighs 40 pounds at 6 months, so substitute $w = 40$ into the formula: $$\text{Adult weight} = 1.5 \times 40$$ 4. **Calculate:** $$\text{Adult weight} = 60$$ 5. **Answer:** The expected adult weight of Britney's puppy is 60 pounds.