How fast is a 1MB broadband line?

This would allow for a maximum speed of 1 Megabit per second.

It will therefore take:
8 seconds to download 1 Megabyte.
839 seconds to download 100 Megabytes.
1074 seconds to download 1 Gigabyte.

These calculations are true IF the line is working at full speed. Sometimes you will not get the full 1 Mbps because broadband speed is affected by several other factors - other users online in your area, your distance from the telephone exchange etc.