The times taken for the calls are: 9, 2, 3, 1, and 5 minutes.
\[ 9 + 2 + 3 + 1 + 5 = 20 \text{ minutes} \]
The number of calls is 5. Thus, the average time per call is:
\[ \frac{20}{5} = 4 \text{ minutes} \]
Thus, the average time per call is 4 minutes.
Arun’s present age in years is 40% of Barun’s. In another few years, Arun’s age will be half of Barun’s. By what percentage will Barun’s age increase during this period?