VERY Confused!

[BadCo55]

Between 1980 and 2000 the population of anendangered species decreased at rate of 0.11% per year. The population P is given by:
P = 1019 · (0.9989)t; where t = 0 corresponds to 1985.

Find the population of the species in:
a. 1980;
b. 1985;
c. 1990;
d. 2000;

I have absolutely no idea what I do with this! Can someone please help!?

 

[BadCo55]

Post something readable...else we can't help...

Sorry about that, i've fixed it now

 

[BadCo55]

OK; we do not do homework here;
can you explain why you have "no idea"?
Like, why would you be given this problem if that's the case?
Do you have a teacher? What grade are you in? Thanks.

I'm a senior in high school, I don't understand the concept. I don't know what I should do with the numbers given, I've tried to put the .11 in the exponent and have tried other things but every answer that I enter is wrong. I don't know how to solve this problem. A steer in the correct direction is all I need.

 

[BadCo55]

Geesh......should that not be (.9989)^t ?

It is, my mistake.

 

[BadCo55]

1019 * (.9989)^0 = 1019 * 1 = 1019 : 1985 population

1980: 1019 / (.9989)^5 = 1024.623... : the ^5 if from 1985 - 1980 = 5

1990: 1019 * (.9989)^5 = 1013.408... : 1990 - 1985

2000: 1019 * (.9989)^15 = 1002.315... : 2000 - 1985

Sure looks like a silly problem to me...
Can you try those in your "answer entry" and let me know if ok...
AND if you need explanation of what I did.

The answers are good, thank you. But, there is another question that is similar, so I would appreciate an explanation.