Question

The world's population has grown at an average rate

Answer 1

Answer:

$P(t)=4(1.019)^t$

Step-by-step explanation:

we know that

The equation of a exponential growth function is equal to

$P=a(1+r)^t$

where

P ---> is the world's population

t ---> is the number of years since 1945

a ---> is the initial population in 1945

r ---> is the percent rate of growth

we have

$r=1.9\%=1.9/100=0.019$

substitute

$P=a(1+0.019)^t$

$P=a(1.019)^t$

Remember that

There were  approximately 4 billion people in the world in 1975

That means

Since year 1975 the initial value a=4 billion people

substitute

$P(t)=4(1.019)^t$