You can create a system of equations. Let x = the age of the man Let y = the age of his son You can create the following equations based on what was given in the problem: 1. x = y + 18 2. (x - 3) = 4(y - 3) You can simplify the second equation: x - 3 = 4y - 12 x = 4y - 9 Then, solve the system of equations: x = y + 18 - x = 4y - 9 ____________ 0 = -3x + 27 The son's age is 9, therefore the father is 27 years old.
