Short Answer
8
Givens
M = Medford
W = Westville
x = number of years
Equations
M = 800 + 30x
W = 1240 - 25x
Problem
When will M = W
Solution
800 + 30x = 1240 - 25x Add 25x to both sides
800 + 30x + 25x = 1240 - 25xb+ 25x Combine like terms
800 + 55x = 1240 Subtract 800 from both sides
800 - 800 + 55x = 1240 - 800 Combine like terms
55x = 440 Divide by 55
55x/55 = 440/55 Combine
x = 8
In 8 years their populations will be equal
Check
M = 800 + 30(8)
M = 1040
W = 1240 - 25x
W = 1240 - 25*8
W = 1040
