Suppose a countrys population in 1980 was 210 million. In 1990 it was 225 million. Using the exponential growth formula, P=Ae^kt, estimate the countrys population in 2000

Verified Answer :

P=Ae^kt

225 = 210 e^(k(1990-1980)

225/210=e^10k
ln(225/210)=10k

k=ln(225/210)/10=0.0069

P = 210e^(0.0069t)

for 2000 ===> t = 2000-1980=20

P = 210
e^(0.0069*20)
P=241.0749=241

Answer:

The countries population in 2000 was 241,08 millions

Step-by-step explanation:

To resolve this exercise we need to know the exponential model:

\(P_(_t_)=P_0*e^k^t\)

Where:

\(P_(_t_)\): The population in certain time

\(P_(_0_)\): Initial population

k: constant

t: time frame

With the problem information we can find the constant (k), because we have all the information in t=10 years (1990-1980=10 years)

\(P_(_1_9_9_0_)=P_(_1_9_8_0_)*e^k^1^0\)

\(225m=210*e^1^0^k\)

\(\frac{225m}{210m}=e^1^0^k\)

We multiply by natural logarithm on both sides of this equation and we have:

\(Ln(\frac{15m}{14m})=10*k\\k=\frac{Ln\frac{15}{14}}{10}\\k=0.0069\)

With the constant (k) we can find the population in 2000

\(P_(_0_)=210m\): Initial population

k=0.0069

t=20 years (2000-1980=20 years)

\(P_(_2_0_0_0_)=P_(_1_9_8_0_)*e^k^2^0\)

\(P_(_2_0_0_0_)=210m*e^0^.^0^0^6^9^*^2^0\)

\(P_(_2_0_0_0_)=210m*e^0^.^1^3^8\)

\(P_(_2_0_0_0_)=210m*1.1479\)

\(P_(_2_0_0_0_)=241.08m\)

The countries population in 2000 was 241,08 millions