Question 1046941
.
I'd classified this formulation as incorrect.


It is not a way to formulate math problems.



"His sister will be 5 years older in 2 years."   - Older than who?  older than who and when?


It is a "bad style formulation". There is NO PLACE for such formulations in math.


It is seen from this post that the author is unfamiliar on how the typical age problems are formulated.


Very bad impression.



And don't mix Math (school math, I mean) with puzzles.