How long is the latency time of a typical hard-disk drive spinning at 360 revolutions per second?

Solution:

The latency time of a typical hard-disk drive spinning at 360 revolutions per second is 5400.

Latency is a measure of delay.  In a network, latency measures the time it takes for some data to get to its destination across the network.  It is usually measured as a round trip delay - the time taken for information to get to its destination and back again.   The round trip delay is an important measure because a computer that uses a TCP/IP network sends a limited amount of data to its destination and then waits for an acknowledgement to come back before sending any more.  Thus, the round trip delay has a key impact on the performance of the network.

Thus the required answer is 5400