Stuck on a word problem

Question

Grinnell Glacier National Park in the US covered about 142 acres in 2007 and was shrinking at a rate of about 4.4% per year.

 

(a) Write a formula for the size, S, of the Grinnell Glacier, in acres, as a function of years t since 2007.

 

 

(b) Use the model to predict the size of the glacier in the year 2015.

Answer 1

(a)

S = 142(0.956)^t-2007

 

(b)

S = 142(0.956)⁸

S ≈ 142(0.697691028)

S ≈ 99.072126

 

In 2015 the glacier shall be approximately 99 acres.