stuck, 135 bytes

Result

WA

Duration

509ms

Code [DL]

ssss["x:map(int,x.split())"mT"x:[x[3]-e for e in x]"mT]yu]u]u][
______________
1&u5&u6&*u3&u8*-*u2&u3&u7&*u4&u6*-*u0&u4&u8&*u5&u7*-*6/

stdin

19 31 84
10 94 20
82 34 32
32 85 04

stdout

548007568-801122-232213252-802.666666667

stderr

strace