ABC26GN5198 · Clocks

Subject: General Aptitude · Chapter: Clocks · Exam: 2006 · Marks: · Difficulty:

A clock strikes once at 10' clock, twice at 20' clock, thrice at 30' clock and soon. What is the total number of strikings in a day?
(a)136
(b)146
(c)156
(d)166
Answer
Answer (as printed): C
Explanation
Total number of strikings $=2(1+2+3+\ldots \ldots .+12)$ $$=2 \times \frac{12 \times 13}{2}=156 .$$

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

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