Sequences and series

The table models a Pay It Forward scheme started by Kelly and her friends at school. How many people will be doing good deeds in the 9th stage?

Mr. Whitman is in a 24-hour dance-a-thon as a part of a fundraiser. He raised $50 in the first hour of the competition, then another $60 in the second hour, then another $72 in the third hour. If this pattern continues, what will be the total amount of money he raises if he stays for the entire competition?

Five years ago, Vanessa bought a car for $25,000. Each year since then, the value of the car has decreased by 12%. What is the approximate value of the car after 5 years?

The population of a city is decreasing by 3% every year. If the population is 125,000 in the 1st year, how many will remain in the 10th year?

You have inherited land that was purchased for $30,000 in 1960. The value of the land increased by approximately 5% per year. What is the approximate value of the land in the year 2011? (51 years)

The number of mosquitoes at the beginning of the summer was 4,000. The population of mosquitoes is expected to grow at a rate of 25% a month. How many mosquitoes will there be after 4 months? (Round to nearest whole number)