I've solve the first part...
now just left with Convert milliseconds to minutes.. thanks so much all of you man!...
i will just Google and see how to Convert milliseconds to minutes...
What's the value of secondTry? Perhaps elapsed_time / 60000 is a multiple of 60? Because TimeUnit.MILLISECONDS.toMinutes actually just divides by 60000.
The first one worked as well, because 4320 % 60 == 0. I would still prefer the second solution though, since it makes it much clearer what you want to do.