s+25=b  (that's wrong!)

I am stuck after this. I don't understand how to come up with the second equation to solve.

Heather


Sue is 25 years older than Bill. 

Sue is the oldest so you have to add 25 to Bill's age to get Sue's age.
Not the other way around. So Sue's age = Bill's age + 25:



in 4 years, Sue will be twice as old as Bill will be in 4 years. How old are they now?

In 4 years, Sue will be S+4 and Bill will be B+4, and S+4 will be twice B+4, so



So the system is


Can you solve that system. If not, post again asking how.

Solution: S=46, B=21

Sue is 46 and Bill is 21.

Sue is 46 which is 25 years older than Bill who is 21.  In 4 years,
Sue will be 50 and Bill will be 25 and she will be twice as old as 
Bill will be in 4 years.  So it checks.

Edwin