Given rpm= 3600 rpm
so in 1 minute it rotates 3600 times,
So, time for 1 rotation = 60/3600 = 1/60 sec
In one rotation, it traverses one track
So, in 1 rotation ,it transfers 512 bytes,
So, 1 second it transfers 60 * 512 bytes= 30720 bytes
Now convert it into Kb = 30720/2^10
=30 KBps