Question

The world's population has grown at an average rate of 1.9 percent per year since 1945. There were approximately 4 billion people in the world in 1975. Which function represents the world's population P, in billions of people, t years since 1975? (1 billion = 1,000,000,000)

Answer 1

Answer:  $f(t) = 4000000000( 1 .019)^t$

Step-by-step explanation:

Here, According to the question,  The population of the world is 4 billion (approx).

Again According to the question, The world's population has grown at an average rate of 1.9 percent per year since 1945.

Therefore, after 1975 the growth rate will remains same.

Thus, the population of the world after t years,

$f(t) = 4000000000( 1+\frac{1.9}{100} )^t$   (By the formula $A = P(1+\frac{r}{100})^t$ )

⇒$f(t) = 4000000000( 1.019 )^t$

Where 1.019 is the growth rate and 4 billion is the initial population.