math challenge!?

Question

i dont even know where to begin:

The human population of the world was about 6 billion in the year 2000 and increasing at the rate of 1.3% a year. Assume that this population will continue to grow exponentially at this rate. Determine the year in which the population of the world will reach 7 billion.

any help would be greatly appreciated!!! (i need to show work also)

Answer 1

Use the population growth formula. N(t)=n0*e^(rt). the n0 is read as n sub zero and is the initial population, r is the rate (in decimal), and t is time. Once you set up the equation you can substitute in 7billion for N(t) and solve for t.

Answer 2

Take 6 billion, and multiply that by .013 (which is 1.3%). Call that n1. That will be 2001. Take n1, multiply that by .013, which is n2. That year will be 2002. Keep up this process until you break 7 billion.

Answer 3

Use logarithms, and it's easy. To set it up, you have this:

7 billion/6 billion = 1.013^k (where k is years)

1.013^k = 7/6

k log 1.013 = log 7 - log 6

k = (log 7 - log 6) / log 1.013 = 11.93 years

So the population ought to hit 7 billion in 2012.

Answer 4

6,000,000,000 times 0.013=78,000,000 people per year

1,000,000,000 divided by 78,000,000=12.82 years

The world should have 7,000,000,000 inhabitants by around late June or early July of 2019.

Answer 5

it will be 'bout mid-2011

Answer 6

cant help