How much money does the Play Store make in a year?

This question requires you to estimate the annual revenue made by Google's Play Store. It's important to note that this is a data-driven company, and actual figures may be confidential or not publicly available. To respond effectively:

1. Understand what the Play Store is: The Play Store is Google's official pre-installed app on Android devices which provides access to content like apps, games, music, movie rentals and purchases, and ebooks.

2. Identify its main revenue sources: The Play Store generates revenue mainly from app purchases, in-app purchases, and subscription services.

3. Make reasonable assumptions: As data on the exact number of downloads, purchases, and subscription costs isn't publicly available, you'll need to make educated assumptions to make an estimate.

Remember, the interviewer isn't looking for an exact figure, but rather your thought process in reaching an approximate value.

For estimating the annual income of the Play Store, I'll start with the knowledge that Google retains 30% of the revenue from paid apps and in-app purchases, while app developers get the remaining 70%. Let's say the average price of a paid app or in-app purchase is around $1. If I assume that 1 billion of the 2 billion Android users worldwide make one such transaction per month, Google would earn $300M per month, or $3.6B per year, from apps alone.

Next, consider subscriptions like Google Play Music and Google Play Movies & TV. If around 10% of Android users have subscriptions at an average cost of $10 per month, this would earn $2.4B per year.

Adding these two values together, a rough estimate of the Play Store's annual revenue could be around $6B. This is an approximation and would depend heavily on actual costs, number of transactions, and the percentage of users making purchases or having subscriptions.

Estimating the Play Store's annual revenue involves multiple assumptions, as exact numbers aren't public knowledge. Google charges 30% on app purchases, in-app purchases, and subscriptions, so the total earnings will largely come from this.

Perhaps half of Android's total user base of 2 billion users participate in these transactions, with an average cost of $0.99 per transaction. Assuming 1 billion users make one transaction per month would lead to monthly earnings of $300M, or annual earnings of $3.6B from app transactions alone.

Then, if we assume about 10% of total users pay for subscriptions at an average of $10 per month, Google would earn an additional 10% * 2 billion * $10 * 12 = $2.4B per year from subscriptions.

Adding these, a rough estimate for the Play Store's earnings per year could be around $6B. This would vary depending on the actual average costs and number of transactions."