Got some networking questions:

7.22 If two signal levels are used, what is the data rate that can be sent over a coaxial cable that has an analog bandwidth of 6.2 MHz?

7.23 If a system has an average power level of 100, an average noise level of 33.33, and a bandwidth of 100 MHz, what is the effective limit on channel capacity?

7.24 If a system has an input power level of 9000, and an output power level of 3000, what is the difference when expressed in dB?

7.25 If a telephone system can be created with a signal-to-noise ratio of 40 dB and an analog bandwidth of 3000 Hz, how many bits per second could be transmitted?

please show formula and how you worked it out so i can understand thats most important.