A certain mountain has an elevation of 19,206 feet. In 1909, the glacier on the peak covered 6 acres. By 2000, this glacier had melted to only 1 acre.
a) Assume that this glacier melted at a constant rate each year. Find this yearly rate.
b) Use your answer for the part (a) to write the linear equation that gives the acreage A of this glacier t years past 1909.

The yearly rate of change is ____ acres/year.

What is the equation that gives the acreage of the glacier t years after 1909?

Question

A certain mountain has an elevation of 19,206 feet. In 1909, the glacier on the peak covered 6 acres. By 2000, this glacier had melted to only 1 acre. 
a) Assume that this glacier melted at a constant rate each year. Find this yearly rate. 
b) Use your answer for the part (a) to write the linear equation that gives the acreage A of this glacier t years past 1909. 

The yearly rate of change is ____ acres/year.

What is the equation that gives the acreage of the glacier t years after 1909?

anonymous · Answer

Since the rate of melting is constant, the rate of melting is the total amount of melting divided by the total amount of years.

Change in glacier coverage / change in years = (new coverage - original coverage) / years
= (1 acre - 6 acres) / (2000 - 1909)  = -5 / 91

So the glacier loses 5/91 of an acre each year.