The average of the two-digit numbers, which remain the same when the digits interchange their positions, is-

A. 33

B. 44

C. 55

D. 66

Answer: Option C

Solution(By Examveda Team)

Average
$$ = \frac{{11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 + 99}}{9}$$
$$ = \frac{{\left( {11 + 99} \right) + \left( {22 + 88} \right) + \left( {33 + 77} \right) + \left( {44 + 66} \right) + 55}}{9}$$
$$\eqalign{ & = \frac{{4 \times 110 + 55}}{9} \cr & = \frac{{495}}{9} \cr & = 55 \cr} $$