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In the advanced Nutripremium case:

Anonymous A

Assuming that a woman on average has 2 kids i.e. 18 months (1.5 years) in pregnancy. Assuming the average life span of a woman as 75 years. This gives me that on an average a woman will be pregant for 2% of those 75years.

How does that lead me to the conclusion that 2% of the women population will be pregnant at any given time.

Please suggest.



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replied on 09/12/2018
Experienced strategy consultant, now running own consulting business

Should be evident - maybe this will things clearer:

  1. imagine that all women were born on the same day and die on the same day.
  2. Now assume that a pregnancy will occur at a random point in their life (not between 20 and 40)
  3. Then at any given time, it can be expected that 2% of women are currently pregnant
  4. Now obviously not all women are born the same day - but obviously, pregnancies don't also occur at a random time in a woman's life. So the random time of birth "corrects" the non-random time of the pregnancy.

(As you should be able to guess by now, the 2% statement is only approximately true, as the age pyramid is not evenly distributed. But for case purposes it's close enough, I guess.)


Vlad replied on 09/12/2018
McKinsey / Accenture / Got all BIG3 offers / More than 300 real MBB cases / Harvard Business School


Here we also assume that all the population is spread equally among the age groups - it means that at any given moment we have the same amount of people of each age.