bearing in mind that there are 60 minutes in 1 degree and 60 seconds in 1 minute.
let's start off by subtracting the degrees, 60° - 30° = 30°.
now, we have 50'40", let's make them all in seconds, let's see 50*60 = 3000 seconds plus 40 = 3040 seconds.
40'50" is 40*60 = 2400 seconds plus 50 = 2450 seconds.
3040' - 2450' = 590'.
so is really 30°590", let's get the minutes from that, 590/60 gives us a quotient of 9 and a remainder of 50, so is 9 minutes and 50 seconds.
