The General Equation of Alkane is as follow,
CnH₂n₊₂ ------- (1)
As m/z = 380
So,
CnH₂n₊₂ = 380
Or,
12n+ 1₂n₊₂ = 380
12n+ ₂n ₊ ₂ = 380
14n ₊ ₂ = 380
14n = 380 - 2
14n = 378
n = 378 / 14
n = 27
Now, putting value of n in eq. 1
C₂₇H₍₂₇ₓ₂₎₊₂
C₂₇H₅₆
Result:
C = 27
H = 56