: = 1mbps , 1

, 1*1024 = 1024kb/s
, 1 = 8 , 1 = / 8
1024/8= 128
= 128 * 60 = 7680
= 128 * 3600 = 460800

= 500
7680 1024 = 7.5
460800 1024 = 450