During the cold winter months, a sheet of ice covers a lake near the Arctic Circle. At the beginning of spring, the ice starts to melt.
The variable
ss
s

models the ice sheet's thickness (in meters)
tt
t

weeks after the beginning of spring.
s=−0.25t+4s=-0.25t+4
s=−0.25t+4

By how much does the ice sheet's thickness decrease every
66
6

weeks