It takes the pendulum of a clock 7 seconds to strike 4 o'clock. How much time will it take to strike 11 o'clock?

- 18 seconds
- 19.25 seconds
- 20 seconds
- 23.33 seconds

### Answer

The more relevant thing in this case is not the number of strikes but the number of time intervals.

If a clock has to strike 4, there are 3 time intervals between the 4 strikes So, in 7 seconds the pendulum elapses 3 time intervals.

To strike 11, there has to be 10 time intervals, which will take (10 x 7)/3 = 23.33 seconds.

**The correct option is D.**