## JamenS 3 years ago In 1987, the Australian humpback whale population was 350 and has increased at a rate of about 14% each year since then. Write a function to model population growth. Use a graph to predict when the population will reach 20, 000.

1. Traxter

Use the compound interest formula you used in the other question.

2. JamenS

sooo wud it b 350(1+1.014)=20000

3. Traxter

Almost, the graph you will draw is 350(1+0.014)^n. Then you will go to the point where the graph equals 20,000 and see how many years it has been.

4. JamenS

290.9?

5. Traxter

290.99 is the correct answer, did you solve it using the graph?

6. JamenS

no im not sure how 2 graph it

7. Traxter
8. JamenS

a)P(t) = 350(1.14)t; the population will reach 20,000 in about 30.9 yr. b)P(t) = 350(0.86)t; the population will reach 20,000 in about 19.5 yr. c)P(t) = 350(0.86)t; the population will reach 20,000 in about 39.1 yr.wwwwww d)P(t) = 350(1.14)t; the population will reach 20,000 in about 25.6 yr.

9. Traxter

Sorry, 290.99 is not the correct answer at all. The interest is 14% (which is 1.14), not 1.4% (which is 1.014). If you put 1.14 into the formula instead of 1.014 you should get the correct answer. Let me know how it goes.

10. JamenS

wud it b A?

11. JamenS

30.8?

12. Traxter

The answer on my calculator is 30.87543347. The correct rounding of this to one decimal place is 30.9. So the answer is A.