Setting up a system of equations is usually effective when solving age word problems involving the ages of two people. Knowing how to solve systems of equations is necessary to solve these types of problems. Other types of word problems involving systems of equations include mixture problems, money word problems, work word problems and rate word problems.
There are a lot of trick Math word problems out there and one of the types you're probably going to run into relates to age. You're going to be given 2 people and you're going to be asked about their relative ages, and you're going to be along those same lines thinking about the passage of time. So when you're doing these problems it's really important to keep track of their current age versus their age in the future or past depending on the problem.
Another thing to keep in mind is that if you're adding time like if time's going by between one equation and the next make sure you're adding that time to the age of both people. If you only add to one person you're going to end up with the wrong equations and the wrong answers. So there's this all passage of time it sounds kind of like metaphysical and these like fancy stuff, that's why you really have to be careful to show all of your work and then please check your work at the end and make sure you have a solution that makes sense in the real world.