Maximum packet size = 256 bytes
Segment lifetime = 30 sec
Bits in sequence number = 8
Maximum number of possible sequence numbers using 8 bits = 256.
So, maximum number of bytes that can be uniquely identified = 256 bytes.
Lifetime of a segment = 20 seconds.
So, maximum amount of data that can be sent in 20 seconds = 256 bytes.
Thus,
Maximum data rate per connection
= 256 bytes / 20 seconds = 12.8 Bytes/ Seconds