Another common type of SAT question is a solve the relationship. The best strategy for these is to remember that they are looking for the relationship between two numbers and not a specific answer. For example, what is the ratio of b to a or what could be the sum of three numbers are both questions where relationships are going to be used. In these cases, substituting numbers instead of variables. 

It is really that simple. The relationship will never change even if the numbers do change. For example, if the ratio of girls to boys in a class is 2:3, it does not matter if there are 100 boys or just 3 boys - the relationship will always be 2:3.