I'm stuck on this: computer network

Using modems to exchange information can be inefficient. Suppose you use a 9.6 Kbps modem to do an on-line chatting from your home computer to a friend's computer. During this transmission, a telephone connection is established. Suppose you are trying to send a long message to your friend. Assume that you are a fast typist, you can type 400 characters per minute where the data size of 1 character is 1 byte. Show that you are using less than 0.6% of the bandwidth capacity of the modem connection. (This example reveals a problem of the dedicated resource assignment in circuit-switching networks.)