Concept:Unweighted price index formulas are not commonly used in practice because they ignore the importance (weights) of different items.Explanation:Weighted indices (like Laspeyres or Paasche) are preferred as they account for quantity or expenditure shares.Unweighted indices treat all items equally, which can be misleading.Therefore, unweighted price index formulas are seldom used in real-world applications.Answer:Option B: seldom used