Posted by **Anonymous** on Wednesday, April 13, 2011 at 9:47am.

he world population at the beginning of 1990 was 5.3 billion. Assume that the population continues to grow at the rate of approximately 2%/year and find the function Q(t) that expresses the world population (in billions) as a function of time t (in years), with t = 0 corresponding to the beginning of 1990. (Round your answers to two decimal places.)

(a) If the world population continues to grow at approximately 2%/year, find the length of time t0 required for the population to double in size.

t0 = yr

(b) Using the time t0 found in part (a), what would be the world population if the growth rate were reduced to 1.6%/yr?

billion people

- Math -
**Henry**, Friday, April 15, 2011 at 11:05pm
Q(t) = 5.3 + 0.02*5.3t,

Q(t) = 5.3 + 0.106t.

a. Q(t) = 5.3 + 0.106t = 10.6 Billion,

5.3 + 0.106t = 10.6,

0.106t = 10.6 - 5.3 = 5.3,

t = 50 years.

b. Q(t) = 5.3 + 0.016t*5.3,

Q(t) = 5.3 + 0.0848t.

Q(t) = 5.3 + 0.0848*50 = 9.54 Billion.

- Math -
**Ruvinka**, Tuesday, December 11, 2012 at 6:34pm
part a is incorrect, the proper answer is:

Q(t)=Qoe^kt

Q(t)= 5.3e^0.02t

2=e^0.02t

ln2=0.02t

t=34.6yr

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