Question

If $a-b=2$, and $aa+bb=cc0$ then find the value of $a-b-2c$.

Answer 1

These problems involve basic number
(i) $aa+bb=11(a+b)$

(ii) $aa,bb$ are two-digit numbers
Hence their sum cannot exceed 198 So c must be 1
(iii) Hence $cc0=110$ This implies $a+b=10$ or $a=6$ and $b=4$
Such problems are part of a category of problems called alphanumerics

$a+b-2c=6+4-2=0.$