A coastal geologist estimates that a certain country’s beaches are eroding at a rate of 1.5 feet per year. According to the geologist’s estimate, how long will it take, in years, for the country’s beaches to erode by 21 feet?

A population grows at the rate of 5% per year. How long does it take for the population to double.

A gardener is planting two type of trees. *Type A is three feet tall and graws at a rate of 14 inches per year. *Type B is five tall and grows at a rate of 9 inches per year. How many year will it take for these trees to grow to the same height?

The front of a roller-coaster car is at the bottom of a hill and is 15 feet above the ground. If the front of the roller-coaster car rises at a constant rate of 8 feet per second, which of the following equations gives the height h, in feet, of the front of the roller-coaster car s seconds after it starts up the hill?

A contractor estimates that 3 persons could rewire Jasminder’s house in 4 days. If, he uses 4 persons instead of three, how long should they take to complete the job?

A contractor estimates that 3 persons could rewire Jasminder’s house in 4 days. If, he uses 4 persons instead of three, how long should they take to complete the job?

A helicopter, initially hovering 40 feet above the ground, begins to gain altitude at a rate of 21 feet per second. Which of the following functions represents the helicopter’s altitude above the ground y, in feet, t seconds after the helicopter begins to gain altitude?

During their daily training race, Carl has to stop to tie his shoes . Melissa, whose shoes are Velcro , continues to run and gets 20 feet ahead of Carl . Melissa is running at a constant rate of 8 feet per second , and Carl starts running at a constant rate of 9.2 feet per second to catch up to Melissa . Which of the following equations , when solved for s, gives the number of seconds Carl will take to catch up to Melissa ?