I am using Excel to try to come up with a schedule for when I will be doing my rounds. I have to do them wwithin thirty (30) minutes from the last time and I don't want to go less than 25 minutes apart. I also don't care if some are 30 mins.

Therefore how do I come up with a formula where I add a random time interval between 25 and 30 minutes to the previous row's time value?

rand()returns a pseudo-random number between 0 and 1.0 inclusive, then the the next interval is`5*rand() + 25`

. – sawdust Aug 23 '12 at 23:32