The data transfer rate over the ADSL connection is 256000 bps. How long does it take to transfer a file through

The data transfer rate over the ADSL connection is 256000 bps. How long does it take to transfer a file through this connection (in seconds) if the file size is 500 KB?

There are 8 bits in one byte. We will assume that to transfer one byte, 8 bits must be transferred.

The condition says that the speed of the ADSL connection is 256000 bps, and we decided that for every 8 bits, one byte is transmitted, which means that the transfer rate in bytes will be 32000 bytes / sec:
256000: 8 = 32000 (bytes / sec)

The file has a size of 500KB, and one kilobyte is equal to 1024 bytes, which means that the file size in bytes will be 512’000bytes:
500 * 1024 = 512’000 (bytes)

The file size is 512’000 bytes, the transfer rate is 32000 bytes / sec, which means that a byte will be transferred in 16 seconds:
512’000: 32000 = 16 (sec.)

Answer: 16 sec.