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Question

A linear function can be used to model the decrease in rainfall measured since 1880. The decrease in annual rainfall has been a constant 0.12 inches per year. Let x represent the number of years since 1880, when measurements began, and let y represent the annual rainfall. The initial measurement in 1880 was 54.3 inches. Use the linear function to predict the annual rainfall in the 101st year after recordkeeping began. Round to the nearest hundredth.

Answer 1

f(x) = 0.12x + 54.3, where 0.12 inches per year is the slope and 54.3 inches of rain is the y-intercept (initial value to start when x = 0).

f(101) = 0.12(101) + 54.3 = 66.2

About 66.2 inches of rain occurred in 1981.