At 6′o clock a clock ticks 6 times. The time between first and last ticks is 30 seconds. How long does it tick at 12′o clock ?

A 66 sec

B 55 sec

C 36 sec

D 24 sec

Correct Answer: Option A

For ticking 6 times, there are 5 intervals.

Each interval has time duration of 30/5 = 6 secs

At 12 o'clock, there are 11 intervals,
so total time for 11 intervals = 11 x 6 = 66 secs.