Suppose a clock takes 7 seconds to strike 7. How long does it take for the same clock to strike 10?
Answer
It will take 10.5 seconds for the clock to strike 10.
While striking 7, the clock strikes the first gong at 7 o’clock and it strikes 6 more at regular intervals. These 6 intervals take 7 seconds, so the interval between gongs is 7⁄6 seconds.
However to strike 10, there are 9 intervals each taking 7⁄6 seconds. This adds up to a total of (9 x 7⁄6) 10.5 seconds.