A6.00-kg crate is suspended from the end of a short vertical rope of negligible mass. an upward force f(t) is applied to the end of the rope, and the height of the crate above its initial position is given by y(t)=(2.80m/s)t+(0.61m/s3)t3

So if in 2000, the town at 3901 people, with a decrease of 1.8%, and you want to find the population at 2013, first you want to set up your equation.

3901(1-0.018)^13

the first number being your total population, the inside number being the amount of decrease(make sure its -0.018, if you put a + you would calculate an increase at a rate of 1.8%.) the ^13 is the time, which is 13 years.

Your answer is 3081. Rounded up to a whole number because you cant have a sixth of a person.

Hope this helped