Exercise 8

1) Estimate the number of cigarettes consumed monthly in the US

2) Design a chat app for a couple who live together

Post and review answers and feedback to answers in the comments section of this post.

See also:

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List of estimation questions for product manager job interviews

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Here’s an attempt on Q2:

First thing I want to consider is, how do a couple’s chatting needs differ when they live together vs any other existing chat app? What pain points are currently not addressed?

Drawing from my personal experiences, my chat history with my SO (with whom I live with) are not the same as chat histories with my friends. Rather than conversations and sharing of memes and everyday happenings, they’re full of short, to-the-point Q&As. “Are you coming home today for dinner?” “I’m at the store, do you want anything?” “I just arrived, where are you?” Let’s assume that this Q&A behavior is normal for this target demographic.

What pain points exist in this type of communication? There are time sensitive questions (“I’m at the store now, do you need me to grab anything for you?”) and non-time sensitive questions (“do you want to go hiking with my colleagues this weekend?”) Slow responses to time sensitive questions can lead to responses that are no longer relevant, or direct calls to escalate for immediate attention.

In this new app for couples living together, there will be a feature that allows for varying levels of notification urgency. To accomplish this, there are two new features to introduce:
1) Senders can tag the level of time-sensitivity their message is (low, med, high). Their message will be sent with a corresponding visual cue (through icons or different color text banners) to signify the time sensitivity in the chat log.
2) Users can customize what type of alert to get for incoming low, mid, and high time-sensitive messages for authorized contacts. Customizable alerts include varying notification banners, vibration or audio settings.

Before diving into design & development, I would conduct a survey with other couples to validate these ideas first.

What are your thoughts? I’d love to hear any feedback!

Product Management Exercises

Thank you for posting your answer to the question. I think it’s a good answer. I really like following the CIRCLES method highlighted in the book “Decode and Conquer”. It suggests that before soluionining, highlight a few needs and select the highest priority need (explain your thoughts process on selecting the highest priority need). If I was going to do this exercise, I would have first listed a few more needs that are unique to the couples and then I would have explained my logic behind why knowing the level of urgency of a message is a high priority need. Overall, I think the answer is good and demonstrates your ability to find a pain point and come up with creative solutions.


To calculate total number of cigarets consumed monthly in the US, I would calculate the estimated total number of cigarets consumed in each age group and add all the numbers. For simplicity reasons, I’m going to assume the population is distributed equally among the age range of 0 to 80. In other words, there are about 4million people in each age year. I will also assume that the population of the U.S. is about 320million. Here is my breakdown on the volume of cigarets consumed per age group;

0 to 12 years of age – (12/80)% of the population – smoke 0 cigarrets per day, meaning they smoke 0 cigarets per month.

12 to 20 years of age – (8/80)% of the population – assume 15% of people in this age group smoke about 5 cigarets per day. Meaning 10% x 15% x 320million x 5 cigarets per day x 30 days = about 750 million cigarets per month

20 to 60 years of age – (40/80)% of the population – assume 10% of people in this age group smoke about 10 cigarets per day. Meaning 50% x 10% x 320million x 10 cigarets per day x 30 days = about 4,800 million cigarets per month

60 to 80 years of age – (20/80)% of the population – assume 10% of people in this age group smoke about 5 cigarets per day. Meaning 25% x 10% x 320million x 5 cigarets per day x 30 days = about 1,200 million cigarets per month

(Note that for simplicity, I’ve assumed that the rate of smoking among the city and non-city people is equal. and I’ve also assumed men and women smoke at the same rate. I could have broken each age group into 4 additional groups by considering a different % of smokers and # of cigarets per day based on location and gender).

So, total number of cigarets consumed per month is 0 + 750 million + 4,800 million + 1,200 million = 6,750 million or almost 7 billion cigarets per month.