Hi! I have the answer key to this- but having some problems working through a lot of these questions. If someone could help with how to work through these problems, it’d be greatly appreciated. Thanks in advance!

Test 2 Practice

For problems 1-8:

a)    Identify the independent and dependent variables

b)    Determine the linear or exponential model

c)     Answer the question(s)

1.    The population of Happy Town is growing at a rate of 5% per year. In 2000, there are 100 people in Happy Town, how many live there in 2020?

2.    Every year since 1975, the population of Shrink Town is decreasing by 20 people. In 1975, the population was 1500. When will the population of Shrink Town reach zero?

3.    In 2050, there are 5000 people living on Mars. In 2060, there are 6500 people living on Mars. The population of Mars in increasing at a constant rate. How many people are living on Mars in 2075?

4.    Little Johnny buys two magic sea monkeys. The number of magic sea monkeys increases at a rate of 18% per hour. If 1275 sea monkeys will fit in the magic monkey habitat, how long until the habitat over flows?

5.    Gary Gamer goes into the video arcade with $25. He spends $1.25 every 30 minutes. How many hours until half of his money is gone?

6.    Rhonda Runner is increasing her running distance at a rate of 12% per week. If she begins by running 2 miles, how long until her running distance is 5 miles?

7.    A certain drug leaves the bloodstream at a rate of 22% per hour. If you are given an initial dose of 20 mg, how long until there are 10 mg in your bloodstream?

8.    The number of flu cases in a community is increasing at a rate of 5 cases per week. In the fourth week of flu season, there are 38 reported cases. How many people were initially infected with the flu? How many cases do you expect in week 20?