plz help me!

Let 5 numbers be x₁, x₂ ,x₃, .....x₅

x₁₊ x₂ +x₃, ....+.x₅= 27X 5.......(i)

If x₅ is excluded then x₁₊ x₂ +x₃, ....+.x₄ = 25X4 .......(ii)

_So x_{5 is given by (i)-(ii)}

= 135-100 = 35

_{So 35 is the excluded number}