Can you provide an estimate of how many trees are in the city of Delhi?

This task is a guesstimate or a Fermi problem question. The interviewer wants you to demonstrate your critical thinking abilities and show that you can handle numerical analysis under some pressure. You should make sensible assumptions about the circumstances and articulate them clearly, then use these assumptions to derive an estimate, outlining your reasoning throughout the process. Here are some important points to keep in mind: Formulate reasonable assumptions and express them clearly. Don't hesitate to request clarification or additional information if necessary. Utilize simple round numbers for your calculations. Clearly explain your methodology for arriving at the estimate. Adopt a step-by-step method to reach your final estimate. Articulate your thought process.

To tackle this problem, I would start with a few assumptions. First, let's consider that the area of Delhi is around 1500 square kilometers. Next, if we assume that approximately 30% of this area is forested, that would mean around 450 square kilometers is occupied by trees. With an average tree density of about 1000 trees per square kilometer, we can roughly estimate that there are about 450,000 trees in Delhi. This is a general estimate and could be refined with more precise information.

Here’s one method we could use for estimation. Let’s assume that Delhi has 20% of its area designated as green spaces, which include parks, street trees, and small woodlands. With an estimated total area of about 1500 square kilometers for Delhi, this translates to approximately 300 square kilometers of green space. However, not all of this space is covered solely by trees; let's estimate that around 50% consists of trees, resulting in 150 square kilometers. If we assume there are roughly 750 trees per square kilometer, this leads us to estimate around 112,500 trees throughout the city of Delhi. Naturally, these figures are approximate and depend on the availability of precise data.