question: The graph shows the cost, in dollars, of a phone call for different call durations. The x-axis represents call length (minutes), and the y-axis represents call cost.
  
  What is the average rate of change?
  
query_wo: Please directly answer the question and provide the final value, e.g., 1, 2.5, 300.
  Question: The graph shows the cost, in dollars, of a phone call for different call durations. The x-axis represents call length (minutes), and the y-axis represents call cost.
  
  What is the average rate of change?
  
query_cot: Please first conduct reasoning, and then answer the question and provide the final value, e.g., 1, 2.5, 300, at the end.
  Question: The graph shows the cost, in dollars, of a phone call for different call durations. The x-axis represents call length (minutes), and the y-axis represents call cost.
  
  What is the average rate of change?
  
question_for_eval: The graph shows the cost, in dollars, of a phone call for different call durations. The x-axis represents call length (minutes), and the y-axis represents call cost.
  
  What is the average rate of change?
  