UPSC Civil Services 2017 Prelims General Studies Paper II

At 5’ o’clock it strikes 5 times. Total gaps between 1 to 5.
(1 – 2 – 3 – 4 – 5) Total time for 4 gaps.
So, time taken for each gap =

12

4

= 3 sec.
At 10’o clock, it strikes 10 times.
Total gaps = 9
Hence, 9 × 3 = 27 seconds.