ABC26GN1550 · Average

Subject: General Aptitude · Chapter: Average · Exam: · Marks: · Difficulty:

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

Answer (as printed): C

Explanation

Average $=\left(\frac{11+22+33+44+55+66+77+88+99}{9}\right)$ $$\begin{aligned} & =\left[\frac{(11+99)+(22+88)+(33+77)+(44+66)+55}{9}\right] \\ & =\left(\frac{4 \times 110+55}{9}\right)=\frac{495}{9}=55 . \end{aligned}$$

Explanation as extracted from the printed page; notation may be imperfect.

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