A small rural town has experienced a population decrease at a rate of 25 people every 5 years since 1970. If the population of the town in 1970 was 250, which of the following equations represents the town's population as a function of time? (Assume 1970 is represented by x = 0, 1971 is represented by x = 1, and so on).

A. y = - 5x + 250

B. y = - 25x + 250

C. - 5x + y = 250

D. - x - 25y = 250

Question

Aubrey Davies

Mathematics

27 June, 00:00

A small rural town has experienced a population decrease at a rate of 25 people every 5 years since 1970. If the population of the town in 1970 was 250, which of the following equations represents the town's population as a function of time? (Assume 1970 is represented by x = 0, 1971 is represented by x = 1, and so on).

A. y = - 5x + 250

B. y = - 25x + 250

C. - 5x + y = 250

D. - x - 25y = 250

+4

Answers (1)

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Booth · Answer 1

Here y is the population and x is the year since 1970.

The "population decreases at the rate of 25 people every 5 years"

slope of a line = difference in y / difference in x (or rise / run) = - 25 / 5

slope m = - 5

when x = 0 (that is the year 1970), the population is 250.

x = 0 represents the y-intercept

Answer is C. - 5x+y=250