For gray 1 pixel = 1 byte.
for color 1 pixel = 3 byte;
64kbps =64 kilo bit per sec;
64kbps= 64/8 kilo byte per sec= 8000 byte per sec;
so 540 gray pixels, time=540/8000=0.067sec;
for color 540 pixels, time= 540*3/8000=0.202 sec;
In transmission its considered as download and upload
so, we have 64kbps
Divide by 8 to get the download speed so its 8kbps ie 8192 bits per sec
Now consider the image its 540Bytes convert into bits its 540*1024 = 552960
So divide both 552960 / 8192 = 67.5 sec
i.e., 1 min 7 secs