given: the number of people living in a city is shown by: f(x)=120(.80)^t;f(t) is the number of people (in thousands) after t years
a) is the population of that city increasing or decreasing and how do you know?
b)how many people where living in this city when this data was collected
c)how many people will be living in this city at the 4 year mark? round to the nearest thousand.

Question

given: the number of people living in a city is shown by: f(x)=120(.80)^t;f(t) is the number of people (in thousands) after t years
a) is the population of that city increasing or decreasing and how do you know?
b)how many people where living in this city when this data was collected
c)how many people will be living in this city at the 4 year mark? round to the nearest thousand.

yagosik · Answer

Sorry, I don't understand the formula. Is it$$f(x)=120\times 0.8^t $$?

hale_taylor · Answer

Yes

yagosik · Answer

a) You just need to compare the results for the different time (for example, you can take first and second years)
b) When you have question like this, it usually means the starting point (x=0, or t in our case)
c) Just put t=4
d) Nice hare there was