Settings: There are X computers.
3(X+ 1)=4(X- 1)+3
X=4
Employee: (4+ 1) * 3 = 15
2."253"
Suppose: one is X, ten is Y, and one hundred is Z.
According to the meaning, then: y = x+z
Y-x = 2 = z (so the hundredth is 2)
So: 200+x+10y+99 =100x+10y+2.
Namely: 299+x = 100x+2.
99X=297
X=297/99=3
Y = 5, because X = 3 and Z = 2.
Checking calculation: 253+99 = 352