24 11. The owners of a nature reserve decided to increase the area of the reserve covered by trees. Tree planting started on 1st January 2005. The area of the nature reserve covered by trees, A km 2, is modelled by the equation A = 80 – 45e ct where c is a constant and t is the number of years after 1st January 2005. Using the model, (a) find the area of the nature reserve that was covered by trees just before tree planting started. (1) On 1st January 2019 an area of 60 km 2 of the nature reserve was covered by trees. (b) Use this information to find a complete equation for the model, giving your value of c to 3 significant figures. (4) On 1st January 2020, the owners of the nature reserve announced a long-term plan to have 100 km 2 of the nature reserve covered by trees. (c) State a reason why the model is not appropriate for this plan. (1) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________