Question 205202
The combined population of Marysville and Springfield was 25,000 in 2000.
 By 2005 the population of Marysville had increased by 10%, while Springfield
 had increased b 9%. 
If the total population increased by 2380 people, then what was the population of each city in 2000?
;
Let m = Maryswille population in 2000
Let s = Springfield population in 2000
:
Yr 2000 equation:
m + s = 25000
s = (25000-m)
;
Yr 2005 equation for population increase
.1m + .09s = 2380
;
Substitute (25000-m) for s in the above equation, find m;
:
:
Check solution in the pop increase equation
.1m + .09(25000-m) = 2380
.1m + 2250 - .09m = 2380
.1m - .09m = 2380 - 2250
.01m = 130
m = {{{130/.01}}}
m = 13,000 is pop of Marysville in 2000
and
25000 - 13000 = 12,000 pop of Springfield