Rate word problem////////////////////////////////////////////

i tried!


In 2000, the population of Town A was 9,400 and the population of Town B was 7,600. Since then, each year the population of Town A has decreased by 100 and the population of Town B has increased by 100. Assuming that in each case the rate continues, in what year will the two populations be equal

Short and simple, your answer is 2009.

You can write a system of linear equations to solve this. Use the increase or decrease of the population as the slope and the starting population as the y-intercept. So, you have y=-100x+9400 and y=100x+7600. Solve the system to get x=9, and since your problem started in 2000, your answer will be the year 2000+9=2009.

9400 - 100n = 7600 + 100n

=> 200n = 1800

i.e. n = 1800/200 = 9

so, 2009

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