please solve this question on paper neat work .

There is only one telephone in a public booth of a railway station. The following tables indicate the distributions of callers' arrival time and duration of the calls ..

Time B/w arrivals(minutes) 5 6 7

Probability 0.20 0.70 0.10

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Call duration (minutes) 2 3 4 5

Probability 0.25 0.6 0.5 0.1

Simulate for 100 arrivals of the current system. It is proposed to add another telephone to the booth. Justify the proposal based on the waiting time of callers.