Population Grown in Your Lifetime Starting from the 68 billi

Population Grown in Your Lifetime. Starting from the 6.8 billion population in 2009, assume that world population maintains its current annual growth rate of 1.2%. What will be the world population when you are 50 years old? 80 years old? 100 years old?

Solution

Let us assume starting point or initial population as that of 2009

P0 = 6.8 billion

Growth rate = 1.2% =0.012

Hence P (t) = P0(1.012)^t where t is the no of years counted from 2009.

Now I am 20 years old.

So when I am 50 years old, year = 2046 and t = 37

So P(37) = 6.8(1.012)³⁷ = 10.5727 billion

----------------------------------------------------

When I am 80 years old t = 37+30 = 67

P(67) = 6.8(1.012)⁶⁷=15.1218 billion

-------------------------------------

When I am 100 years old

t = 67+20 =87

P(87) =6.8(1.012)⁸⁷

= 19.1961 billion