4 day work week

Is there a possibility that your boss will allow you for a 4-days work week? Or a shorter working hour from our standard 40 hours to 32 or 35 hours ? 

A lot of my colleagues will say a Yes if you are willing to take a pay cut. Is it necessary? 

Does longer worktime equate to better productivity ? Research shown that we are probably productive for 3 to 4 hours per day. 

Most part of the working time is used for unproductive stuff like clearing tons of rubbish emails and attending meetings that are not needed. 80% of our worktime is used to clear unimportant stuff. For business wise, 20% of your clients probably contribute to 80% of your sales. So why waste that remaining time on unproductive partners or customers ? Why not focus that 30 to 35 hours work week on pure productive work? Time management seems like a chore but it helps us to focus. We can even cut down the work time even more. 

Having said on the 4 day work week plan, we must also ensure that the time saved are put into self enrichment or useful purposes. If not, don't bother pursuing. I am planning to bring to my boss, but need to work on the 'saved' time. Good luck to all!