Question

Two ocean beaches are being affected by erosion. The table shows the width in feet of each beach at high tide measured where 1995 is represented by year 0.
A. Describe the patterns shown by the erosion data measurements shown for each of the beaches in the table.
B. Between which years will the beaches have approximately the same width?
C. Assuming these rates remain constant, what can you do to get a better approximation of when the two beaches will have the same width?

Answer 1

Answer:

A:linear function for both :

beach: y=-2x+100 (x=0, y=100)

dunes=5x+20 ( when x=0, y=20 (year1995)

B: after almost 11 years: it will be year 2006  and 2007 (after 11.429 years)

C: when the two rates of erosion are equal at the rate of 77 and almost 11 years

-2x+100=5x+20

-2x-5x=-100+20

-7x=-80

-80/-7=x

x=11.429

y=77.143