HELP!!

The population of a region is growing exponentially. There were 20 million people in 1980 (t = 0) and 56 million in 1990. Find an expression for the population at any time t, in years. Use the general exponential function and remember to use exact values.
P(t) = ________in millions)

What population would you predict for the year 2000? __________million people

What is the doubling time? (Round your answer to one decimal place.) ________years

Question

HELP!!

The population of a region is growing exponentially. There were 20 million people in 1980 (t = 0) and 56 million in 1990. Find an expression for the population at any time t, in years. Use the general exponential function and remember to use exact values.
P(t) 	= ________in millions)

What population would you predict for the year 2000?   __________million people

What is the doubling time? (Round your answer to one decimal place.)   ________years

anonymous · Answer

The formula for exponential growth of a population with growth rate r is given by

$$P(t) = P_0 r^{t}$$

When t = 0, we get $$P(0) = P_0 = 20 million $$
When t = 10, find the P(10) to solve for r.
Now, substitute P(0) and r in P(t) to find the growth formula.