Edwin is four times as old as Joshua. In 12 years, Joshua's age will be half that of Edwin's. How old are they?

Assign variables to their age.

Let the age of Edwin be e and that of Joshua be j.
Edwin is 4 times as old as Joshua;
e = 4j

You need to multiply Joshua's age by 4 to get them to equal each other.

In 12 years, Joshua's age will be half that of Edwin.
(e+12) = 2(j+12)

Does that make sense?

Can you post back with your answer? It is just a matter of simultaneous equations :)