Question 1178808
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Had your post be presented accurately,  I would show/teach you,  how to solve this  (and similar)  problem/problems.


But for the person who presents  Math problem in this way,  I will do  NOTHING.



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Regarding the solution by @MathLover1,  I can say, that for a standard/routine/regular 
school Math problem,  the solution should not be longer than  10  lines of the standard text  (as an average).



If it is significantly longer,  I'd think that something is out of the order in the solution.


I'd say then,  that something is out of the order  EITHER  in the solution itself,  OR  in its methodology,

OR  in the way of teaching.



Actually,  there is a clear,  straightforward classic elegant solution 

to this and similar problems in  5 - 6  lines long.