lemmie see now..

first the subject:
Kbps and KB/sec
Kbps = KB/sec this is the same

next.. the meat and potatoes..
6-8 Kb/sec = estimated/calculated/approximated download speed..
translates to 6Kb*60 seconds = 360Kb/min (roughly 33% or 1/3 MB)

1 MB = 1024 KB = 1.048.576 bytes
5 MB = 5120 KB = 5.242.880 bytes
1 min = 60 sec = 1/60 hr
11 min = 660 sec = 11/60 hr

5.242.880 bytes / 660 sec = 7943.7575757575757575 b/sec

convert to kilobytes..
7943.757575757575757575 bytes / 1024 = 7.757575 Kb in one second

so your estimate of 6-8Kb/sec is right on and 11 minutes is about right.

synopsis:

1TB = 1024GB = 1.048.576MB = 1.073.741.824KB = 1.099.511.627.776 bytes.. not bits
thats next..

any of the above TB, GB, MB, KB, bytes etc.. etc.. multiplied by an amount of time
equals amount/time e.g. : Kb/sec or b/sec

now for bits vs bytes..
8 bits to 1 byte

the letter 'A' in ascii is represented as a binary value of '01000001' <see all 8 bits?
so the letter 'A' = 1 byte or 8bits

There are a million variables that can affect download speed, knowing this isnt one of them.

"Drink your milk, stay in school.."