Striking the time
Algebra
Level
2
An old-fashioned clock takes 30 seconds to strike six o'clock.
How long will it take to strike twelve o'clock, in seconds?
Assumption: Each strike is instantaneous, and the interval between strikes is constant.
The answer is 66.
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1 solution
When it strikes six o'clock, there are five intervals between the first and last strike. So each interval is 6 seconds long.
When it strikes twelve o'clock, there are eleven intervals. 11 * 6 = 66 seconds.