Final answer:
The probability that a dog at the park is a golden retriever is 4/10, or 0.4, which is also 40 percent.
Step-by-step explanation:
The student asks about the probability that a dog at the park is a golden retriever based on Chester's observations. To calculate the probability, we use the formula:
Probability = (Number of favorable outcomes) / (Total number of outcomes)
In Chester's case, the number of golden retrievers he observed (favorable outcomes) was 4, and the total number of dogs at the park (total outcomes) was 10. Therefore, the probability is 4/10, which simplifies to 0.4, or 40% when expressed as a percent.