Question 1119797
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Certainly a solution using formal algebra can be a good exercise; however, note that if this were a question on a competitive exam where speed is important, the answer can be found much more quickly using trial and error.<br>
14/(1+4) = 4?  Nope.
25/(2+5) = 4?  Nope.
36/(3+6) = 4?  Yep.  Done.<br>
Note further that a very experienced problem solver might solve the problem even faster by noting that, since the number divided by the sum of its digits is 4, the number has to be divisible by 4.  The only2-digit number with tens digit 3 less than the units digit that is divisible by 4 is 36.