450 square feet of the field were covered with weeds. Each year, Gloria removes 35% of the weeds. Which equation can be used to model the area covered with weeds, t, in square feet, as a function of the number of years, y, Gloria has owned the field?

Question

Mathematics

Scott Moses

22 July, 14:22

450 square feet of the field were covered with weeds. Each year, Gloria removes 35% of the weeds. Which equation can be used to model the area covered with weeds, t, in square feet, as a function of the number of years, y, Gloria has owned the field?

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Answers (1)

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Carlo Haas · Answer 1

This is an example of exponential decay.

F = P (1 + r) ^t

F = future value

P = present value

r = yearly rate as a decimal (for decay, r is negative)

t = time in years

F = 450 (1 - 0.35) ^t

In your case, just change the variables.

t = 459 (1 - 0.35) ^y