Answer:
24
Step-by-step explanation:
You want Sam's age if his mother is twice as old, and Sam will be as old in 12 years as his mother was 12 years ago.
If we let m and s represent the mother's age and Sam's age now, respectively, the latter relation tells us ...
s +12 = m -12
Rearranging gives ...
m - s = 24
Sam's mother is twice as old as Sam, so we have ...
m = 2s
Substituting into the above equation gives ...
2s -s = 24 . . . . . . substitute 2s for m
s = 24 . . . . . . . . simplify
Sam is now 24 years old.
