List of Product manager questions

1. One executive says that Feature A is more important and another executive says Feature B is more important. How do you choose which one to implement?
2. Talk about how you overcame product failures/challenges or poor feedback.
3. What’s the best way to work with executives?
4. How do you think product managers interact with engineers?
5. Tell me about a time when you had to build or motivate a team.
6. What is a product you currently use everyday, why and how would you improve it?
7. How do you know if a product is well designed?
8. Suggest a new feature for Amazon. What metrics would you use measure it’s success?
9. What metrics do you think would be important for us to track?
10. How many iPads are sold in the U.S. every year?
11. How do you think we came up with the price for _____ product?
12. How many windows are in New York City?
13. How many people are currently online in Europe?

Product Manager Estimation Question: Exercise #1

If you are opening a new Walmart store, how would you decide how many cash register is needed for the store?

There are basic steps to solve this problem. They are:

1. Ask any clarifying questions. Work with interviewer to define the scope. 
2. Create a main equation such as a = b * c. Divide the equations into sub parts. 
3. Think of any edge cases. 
4. Calculate the numbers and do a sanity check.

Starting with steps:

Questions and Answers by the candidate. 

Questions and Answers by the interviewer. 

Ask clarifying questions to define the scope of the problem:

• Do we know if this walmart is in a suburb or city? Suburb 
• Do we know if there are any other walmarts in the neighborhood? Yes two more. 
• Are they closer to this suburb? No. Both of them are far. 
• Ok so in that case, many of the residents will rely on this Walmart. Yes. 
• Can we assume that any person is ok with waiting at the register for 4-8 mins? Yes

Create the main equation:

Number of registers = Number of people visiting the store/time taken at each register. 

Break down the equations into simple sub-equations: 

• Two main components are: Number of people visiting the store. 
• Time taken at each register: 4-8 mins as clarified. 
• So we need to focus on number of people. Basically only a certain set of people visit the store so we can say x% of entire population visit the store. 
• Since we have no way of telling what is x but given that Walmart is popular choice of lower to upper middle class. We can safely assume that x=65-70% people visit Walmart because of their low prices. 
• Since its a suburb whose size we don't know, we are going to estimate. 
• US average population is 325 million. We will round it to 300 million for easier calculations. 
• Based on some stats I know that:
• 26% population live in urban areas
• 51% in suburban
• 21% in rural
• Majority of population is living in suburban. Estimated number is 150 million live in suburban.
• There are 50 states in USA. We can assume that each state has 50-60 suburbs and bigger ones will have 65-80 suburbs. So average is 60(round off) suburbs in each state. So total suburbs are around: 50*60= 3000 = 3k
• So 150 million people live in 3k suburbs. And on average 50k people live in 1 suburb. 
• Only 65%(as assumed)of 50k go to Walmart. But they go as a family. So we don't need to calculate all the people. We need to calculate the households. 
• We can assume that each household has approximately 3 people. This brings down our number of people to 16k users. 
• And not all the people are at the walmart at the same time. We can say at any time only 5% of people are at a walmart = 5% of 16k = 800 approximately. 
• Now not everyone is checking out at the same time. Let's say only 30% of them are. this brings down the number to 240.
• And not all 240 has shopping carts, they are with their families. Let's say each group has 2 people ~ 120 are in line. 

Calculate the numbers and do a sanity check:

• Equation: Number of registers = Number of people visiting the store/time taken at each register. 
• Sub equation: Number of registers = (x% of total population visit the store)/time taken at each register. 
• x% of total population that visit the store and are doing a checkout during busiest times are = 120
• Average time taken at each register = 6 minutes. 
• So total registers = 120/6 = 20
• Sanity check: At a walmart, I have seen 15-20 registers and our answer is 20. So this is in the ballpark number. 

Final answer is = 20 registers.

Some background: 

• Initially I assumed 30 suburbs in each state. The count came down to 100 million people in each suburb. This is a lot. San Jose's population is 1 million. So I went back and changed the number of suburbs to 60 per state. This helped with some corrections. 
• I assumed 30% of suburbs population is in Walmart at any given time. Again this is a huge number. So fixed it to 5%. 
• Then assumed 50% of them are checking out at the same time so fixed it to 30% as well. 

Let me know your thoughts and let me know in comment section on how you will solve this problem.