Time log into Decimals

Hello,

I need help finding the right formula to change hours/minutes into a decimal. I have a time tracking sheet where I input start times and end times and in the right most column I have a simple formula that subtracts end time from start time to give me the number of hours/minutes total. For invoicing purposes, I need that total time to automatically convert to a decimal so that I can use it as a multiplier with our hourly rate.

For example:

If I start a project at 1:40 PM and end at 2:30 PM it took me 50 minutes The value of 50 min is not useful when I go to invoice the time spent on this project. In order to multiply the total time spend on this project by our hourly rate, which in this case say it is $160, I need to then calculate 50 minutes into a decimal by dividing by 60. For clarity, this is what I need the decimal value for: 50/60 = 0.83 so $160 * 0.83 = 132.80.

How can I do this easily, without having multiple columns for time start and time end and then another for the formula. I need this to be quick and easy because we cannot customize every single time entered by doing special formulas for each specific time entered. Please help!!!!

Thank you