Estimate the number of trees in the city of Delhi.

To tackle this guesstimate question, start by breaking down the problem into manageable components. Consider the area of Delhi and its population density, then make reasonable assumptions about the average number of trees per square kilometer or per capita. Think about factors such as urban versus rural areas, parks, and green spaces that may influence tree density. Clearly articulate your thought process and assumptions as you work through the estimation, and be prepared to adjust your numbers based on feedback or additional information from the interviewer.