I would first confirm if the interviewer is referring to New York City or the state of New York. Assuming, they are referring to New York City, I know the population of NY is about 10M.

Now, I want to find out how many patients can a dentist serve. This will help me calculate the total number of dentists needed to serve 10M.

To estimate the number of patients a dentist can support, I need to estimate the number of hours a dentist spends on a patient. I typically visit my dentist twice a year and each visit takes 30 mins. However, once every 4 years, I make a longer visit (say an oral surgery, root canal, etc) that lasts for about 2 hours. In other words, I spend about 2x30min+(1/4)x2hour = 60min + 30min = 1.5hour per year with a dentist. Now, it’s important to remember that the average time per year per patient varies depending on the age group and insurance status. You can ask the interviewer if they want a more accurate estimate on the average time per patient or not. If they do, you can use a table that helps you show break down of the time spent per patient based on age and insurance status. Something like below (assume people are evenly distributed between 0 to 80, meaning each age group population is 10million / 80 = 125K

0-20 year olds – no insurance – 20% of population in this group = 20% x 20 years x 125K per year = 500K visit 30 min per year

0-20 year olds – with insurance – 80% of population in this group = 80% x 20 years x 125K per year = 2 million visit 120 min per year

20-50 year olds – no insurance – 20% of population in this group = 20% x 30 years x 125K per year = 750K visit 30 min per year

20-50 year olds- with insurance – 80% of population in this group = 80% x 30 years x 125K per year = 3 million visit 150 min per year

50-80 year olds – no insurance – 20% of population in this group = 20% x 30 years x 125K per year = 750K visit 60 min per year

50-80 year olds – with insurance – 80% of population in this group = 80% x 30 years x 125K per year = 3 million visit 180 min per year

(Note that we are making bunch of assumptions on the breakdown of no-insurnace vs. insurance population, time visit per age group, etc). Now, to calculate the average time one spends, just take the average from above time.

(500K x 30 min + 2,000K x 120 min + 750K x 30 min + 3,000K x 150min + 750K x 60min + 3,000K x 180min) / 10,000K = 131 min almost equal 2 hour

For the sake of this report, I will go with 2 hour. Now, we can assume that a dentist works 40 hours x 52 weeks x 75% utilization = 1,560 hours per year. Divid 1,560 by 2 hours and you get 1560/2 = 780 patients. Now, we just need to divide NY population (total number of patients) by 780 (number of patients per dentists) to estimate the total number of dentist in NY:

10Million / 780 = about 12,000.

The answer is about 12,000 dentists work in NY.

2) How would you improve the Uber app?

I would launch a new functionality that lets uber pick up and drop off things for the people who like to deliver things in short distances within same day (e.g. envelops). The beauty of this service is that this doesn’t take the uber driver any passenger room. Also, the driver does not have to immediately start driving in the destination’s direction (unless requested by the sender of the merchandise).

I can measure its adaption based on number of requests coming in per month, additional revenue generated, and the increase in revenue per 8 hour of drive per driver.