What are the most commonly used transmission speeds in BPS used in data communication?

You have a class A network address 10.0.0.0 with 40 subnets, but are required to add 60 new subnets very soon. You would like to still allow for the largest possible number of host IDs per subnet. Which subnet mask should you assign?

Which of the following condition is used to transmit two packets over a medium at the same time?

Frames from one LAN can be transmitted to another LAN via the device

The probability that a single bit will be in error on a typical public telephone line using 4800 bps modem is 10 to the power -3. If no error detection mechanism is used, the residual error rate for a communication line using 9-bit frames is approximately equal to