Question

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 s models the ice sheets thickness (in meters) t weeks after the beginning of spring.
$s = -0.25t + 4$
by how much does the ice sheets thickness decrease every 6 weeks?
meters

Explanation:

Step1: Find the thickness at \(t = 0\)

Substitute \(t = 0\) into \(s=-0.25t + 4\).
\(s_1=-0.25\times0 + 4=4\)

Step2: Find the thickness at \(t = 6\)

Substitute \(t = 6\) into \(s=-0.25t + 4\).
\(s_2=-0.25\times6 + 4=-1.5 + 4 = 2.5\)

Step3: Calculate the decrease

The decrease in thickness is \(s_1 - s_2\).
\(4-2.5 = 1.5\)

Answer:

\(1.5\)