This is part of a mini-series illustrating how to think about estimation prompts for Google interviews. It is also a way to build your logic instincts.

Instructions:

1. See prompt below

2. Think about how you would estimate the answer

3. Identify the variables in your thoughts

4. Derive a simple equation

What you should avoid:

1. Overthinking

2. Trying to get it perfect

Now let’s dive in:

What is the problem:

How many game consoles are sold each year?

Note: If you looked at Monday’s equation, you could argue this could take the same approach. That is essentially true, but we want to think about it another way.

We are not focused on clarifying questions, but one you need to ask here is new vs used. We will consider this is only new, we will not worry about the secondary market.

What are the key elements:

• Population buying first consoles

• Population buying additional consoles

• Population buying replacement consoles

• % of population assumptions

What are the variables?

• X = estimated population buying first

• Y = estimated population buying additional

• Z = estimated population replacing existing consoles

What’s the equation

=X+Y+Z

Today we only care about coming up with an equation. If you want more on how to come up with the numbers to put in your equation, read more here.