Suppose there are 3,000,000 new phone call arrivals
Per minute to the switched telephone system worldwide,
With each call lasting for 5 minutes on average,
And there are 6 hops (i.e. 6 links and 6 nodes) on
Average between the callers and callees. How many
Memory entries are occupied on average to support
The switched connectivity worldwide?

Please help or hint us guys .

You can get the expected time of calls and the expected hops from the given data.

All you need to know is then to find the memory entries required to support each of the components of the call.