Answer:
a. y = 28,000×(1 - 0.07)^t
b. 20,945.46 acres
Step-by-step explanation:
a. The annual percentage decrease in in size of rainforest = 7%
The size of the rainforest in 2009 = 28,000 acres
The exponential decay formula is y = C×(1 - r)^t
Where:
y = Final Amount
C = Initial amount = 28,000 acres
r = Rate of Change = 0.07
t = Time
Which gives;
y = 28,000×(1 - 0.07)^t
b. In 2013 (year 4, t = 4), the amount of rainforest remaining is therefore;
y = 28,000×(1 - 0.07)^(4) = 28,000×0.93^4 = 20,945.46 acres
The size of the rainforest that remained in 2013 is 20,945.46 acres.