Data Com question

Can anyone help me with this problem? I am about to pull my hair out on this one. I’ve solved for PROP of the 150m and the ring, the TRANSP (or TRANSD), and the TRANST. How can I get to the solution? Anyway thanks for any help and here is the problem:

A Token Ring Network using RAT has 128 Data Transmitting Elements w/ an average of 75 meters of copper cabling between successive DTEs. Stations transmit at 4 Mbps. Frames are 1600 bits. Token is 40 bits. Stations may transmit seven consecutive frames before releasing the token. What is the minimum time to transmit a one megabit file to a DTE located 150 meters away? Ignore other overhead and repeater delays.

ANY help would be appreciated, doesn’t have to be the final answer, just some direction on how to get to it.