A wall-clock takes 9 seconds in tinging at 9 o'clock. The time, it will take in tinging at 11 o'clock, is = ?

Answer: Option D

There are 8 intervals in 9 tinging 10 intervals in 11 tinging.
Time duration of 8 intervals = 9 seconds
∴ Required time = Duration of 10 intervals
$$\begin{array}{rl}& =\left(\frac{9}{8}\times 10\right)\text{ seconds}\\ & =11.25\text{ seconds}\end{array}$$