Straight line method formula is depreciable amount / estimated useful life.
Plugging in our data from the problem above:
[(30,000,000 + 2,000,000) - 2,400,000
= ----------------------------------------------------
40 years
32,000 000 – 2,400,000
= ----------------------------------
40 years
29,600,000
= ---------------
40 years
= 740,000 is the depreciation for the first full year.