Question

Laurent Toulemon, demographer at INED (National Institute of Demographic Studies), declares: "In France, in 2018, with a fertility rate of 1.87 children per woman, a generation of 100 women is replaced 30 years later late by 90 girls. ". Verify this statement by calculation. (For this, we will consider that a generation lasts 30 years and that, statistically, 105 boys are born for every 100 girls.)​

Answer 1

Calculation based on a fertility rate of 1.87 children per woman and the given boy-to-girl birth ratio shows that 100 women would be replaced by approximately 91 girls in the next generation, slightly more than the 90 girls stated by Laurent Toulemon.

Step-by-step explanation:

In order to verify the statement made by Laurent Toulemon, we must do a calculation based on the fertility rate and the given ratio of boys to girls at birth.

Assuming there are 100 women, and each woman has 1.87 children, we can calculate the total number of children born to those 100 women:

1. Multiply the number of women by the fertility rate: 100 women * 1.87 children/woman = 187 children.
2. Knowing that there are 105 boys for every 100 girls, we can use this ratio to find out the number of girls:
   1. Total children: 187
   2. The ratio of girls to total children: 100 / (105 + 100) = 100 / 205.
   3. Number of girls = Total children * (100 / 205) = 187 * (100 / 205) ≈ 91.22 girls.

To maintain simplicity, we can round down to 91 girls. Therefore, after 30 years, 100 women will be replaced by approximately 91 girls, not 90 as stated. Laurent Toulemon's estimate is slightly low.