Question

(dads age:  28 years old   when  cindys age : 2 years old .)

Answer 1

So dad=28
cindy=2
so 28-2=diffirance in age=26

A.  dad-26=cindy
      cindy=dad-26
      dad=cindy+26
    so since cindy=18
dad=18+26=44

B. if dad =42=cindy+26 so 
42=x+26
subtract 26 from both sides
16=x
cindy =16 if dad =42

C. so the number of years apart they will be will always be 26 (until one of them dies)