Question 344434
Note: The elder person is "always" 10 years older than the younger person!

Let E be the age of the elder person fifteen years ago!
(E-10) being the age of the younger person.

Question states the following to be true fifteen years ago.
E= 2(E-10)   
Solve
E= 2E-20
20=2E
10=E  the age of the elder person fifteen years ago!

Present Ages!
Elder is now 25 and the younger 15!