I am using Excel 2003.

The situation:
I have instructor to student ratios of 1:36; 1:18; 1:9; 1:4; 1:2; 1:1.

My course requires a total amount of man-hours to be utilized, regardless of the ratio.

All classes going through the course have 36 students.
So, for 1 hour of time spent at a ratio of 1:36 there is only one man hour spent. In 1 hour of time spent at a ratio of 1:18 there are two man hours spent. In 1 hour spent at a ratio of 1:1 there are 36 man hours spent; and so on and so on.

Something else that makes this tricky is that every hour is actually only 50 minutes.

What I need is a way to automatically convert multiple hours of one ratio to the proper amount of hours in another ratio.

Example:
I need Excel to convert 5 hours of 1:18 time to 1:4 time. I need it to look and see that 5 hours at 1:18 is 10 man hours then convert those hours to 1:4man hours, which is 22.5 man hours (I think).

Something else that makes this tricky is that every hour is actually only 50 minutes. so after it gets the 22.5 hours (60 minute hours) I need it to convert that to 50 minute hours.

Jeez I hope this made any sense.