Questions In Interview

Interview Question: How many street lamps are there in Manhattan?


Strategy and Approach to Answering a Problem Solving Interview Question

If you get asked a problem solving question in an interview, remember that they are NOT looking for the RIGHT answer. They are evaluating the approach you use to think out and solve the problem. A strong candidate demonstrates the following:

  1. Evaluates and understand the scope of the problem
  2. Communicates assumptions
  3. Demonstrates quantitative analytical skills
  4. Answers the question that has been asked. You’d be surprised how many candidates get lost in the analysis and solve for a different question than what was asked.



How to Answer this Problem Solving Question

Note, the interviewer is looking for your thought process in this questions.  Using the strategy outlined above, in evaluation we know that Manhattan utilizes a rectangular grid system where there are “streets” on the length side and “avenues” on the width side. Next, let’s assume Manhattan is 100 blocks long and 10 blocks wide, so there are 1,000 square blocks in the city. If each square block has 5 lamps on each side of the street, 20 total in each square block, then the total number of street lamps would be 20 lamps for each square block times 1,000 square blocks, or 20,000 street lamps.

Note: For this problem solving job interview question, there is an actual logical answer, however the interviewer will want to evaluate your thinking process. In answering the interview question, the lead up to your answer will be just as important as the actual answer itself.

For more problem solving, brain teasers, riddles, puzzles, logic job interview questions, please check our out Problem Solving Interview Section.


List of Problem Solving Interview Questions Used by Top Firms (e.g., Microsoft, Google, Goldman Sachs)