Question

in 1900, greenville had a population of 4000 people. Greenville's population increased by 100 people each year. Springfield had a population of 1000 people. Springfields population increased bu 4% each year. In what year were the populations about equal?

Answer 1

Answer: year 1948

Explanation:

1900 is our t = 0

The population of Greenville can be written as:

G = 4000 + 100*t

the equation for Springfield can be written as:

S = 1000*(1.04)^t

we want to find the value of t that makes S(t) = G(t)

4000 + 100*t = 1000*(1.04)^t

(4000 + 100*t) = 1.04^t

4 + 0.1*t = 1.04^t

now, you can graph both of this equations (left side and right side) and see in wich value of t the graphs intersect eachother, or you also may use different values of t until the values are about the same for both sides, which is the thing i did with the equation:

4 = 1.04^t - 0.1*t

You will find that the correct value is t = 48

So we can assume that in year 1948 the populations will be about the same.