Question

A lake near the Arctic Circle is covered by a 2-meter-thick sheet of ice during the cold winter months. When spring arrives, the warm air gradually melts the ice, causing its thickness to decrease at a constant rate. After 3 weeks, the sheet is only 1.25 meters thick.
Let y represent the ice sheet's thickness (in meters) after x weeks.

Complete the equation for the relationship between the thickness and number of weeks.

y=__________

Answer 1

Hi there!

Let the equation be

$y = kx + b$

When x = 0, y = 2

And

when x = 3, y = 1.25

So, b = 2

3k + b = 1.25

=> k = -0.25

b = 2

Therefore, y = -0.25x + 2 (Substituting the two points)

Hope this helps !