Hey dude, I need a help from u. Actually I found this from a Data communication book. 
This is the question I don't need a just answers i need a explanation to understand the theory. 

Four channels are multiplexed using TDM(Time division multiplexing). If each channel send 800 bits/s and it multiplex 8 bits per channel. 
1)What is the size of the frame?? 
2)What is the duration of the frame?? 
3)What is the frame rate?? 
4)What is the bit rate of the output link? 

according to my knowledge,answers should be like below. 

1)32 bits 
2)800 bits-----------------> 1s 
32 bits-------------------> x 
frame duration=0.04 s 
3)frame rate=1/frame duration 
=25 bps 
4)Don't have a idea how to get it .