so Sgt 1 is 15.000 exp .
and 2Lt 1 is 336.000 exp
so 15.000
....-336.000
....=321.000
so u need 321.000 exp .
lats say u earn up to 5500 exp a day .
321.000 : 5.500 = 59 days needed
and if u earn up to 7500 exp .
321.000 : 7.500 = 42 days .
if im wrong that means im bad at math . ^^