Home » Maths for Planet Earth » Arithmetic Afforestation

Arithmetic Afforestation


A country decides to begin a reforestation program, starting in 2020, gradually increasing the number of trees planted per year by the same amount each year.

The timetable for the first four years is shown below:

Year: 2020 2021 2022 2023
Trees planted: 6.0×10 1.4×10 2.2×10 3.0×10

a) Find an expression, in terms of n for the number of trees planted in year n.

[2 marks]

b) Calculate how many trees in total will be planted if this program is followed for 10 years.

[2 mark] 

The government will declare the program a success once 2.45×10 trees have been planted in total

c) Given that the country plants all of the trees that the model would predict in year k, but reaches the target part way through year (k + 1), show that k satisfies 

(2k – 49)(k + 25) < 0.

[5 marks]

Start exploring

Latest from blog

More Maths for Planet Earth

A Level
Human-induced global warming is causing deserts such as the Sahara to increase in surface area. In 1950 the area of the Sahara Desert was
The graph, from the IPCC 1.5 Report, shows how the rate of carbon dioxide emissions couldfall between 2020 and 2040, or between 2020 and
One way of reducing carbon dioxide in the atmosphere and slowing global warming is to plant trees which absorb carbon dioxide from the atmosphere.
Sean works for a town council. He wants to find out how often people use recyling bins when throwing away paper. He is going