S(t) = 3.82 - 0.2t
Step-by-step explanation:
After 7 weeks, the ice is 2.42 meters thick. The ice loses 0.2 meters of thickness per week; this means on the 7th week, it has lost 7(0.2) = 1.4 meters of thickness.
This means the ice started at 2.42+1.4 = 3.82 meters thick.
Our function will start at the original thickness of the ice, 3.82 meters.
Since the ice is losing thickness, we will subtract; it loses at a rate of 0.2 meters per week (t), which gives us 0.2t. This is subtracted from the original, 3.82 meters, giving us
S(t) = 3.82 - 0.2t
