Answer:

X + 2

Step-by-step explanation:

Let the no. be x₁ , x₂ , x₃ ......... x₅₀.

Therefore, (x₁ + x₂ + x₃ + .........+ x₅₀) / 50 = X

                  x₁ + x₂ + x₃ + .........+ x₅₀ = 50 X

But we know that they are consecutive no.

∴, x₂ = x₁ + 1

   x₃ = x₁ + 2(1) = x₁ + 2  ....

   x₅₀ = x₁ + 49

∴, x₁ + x₂ + x₃ + .........+ x₅₀ = 50 X

   x₁ + x₁ + 1 +x₁ +2 + x₁ + 3 ... + x₁ + 49 = 50 X

   50 (x₁) + 1 + 2 + 3 + ... + 49 = 50 X

   50 x₁ + 1225 = 50 X

   x₁ = (50 X - 1225) / 50

If 4 more no. are added, new sum =

x₁ + x₂ + x₃ + ... +x₅₄

(x₁ + x₂ + x₃ + ... +x₅₀) + x₅₁ + x₅₂ + x₅₃ + x₅₄

50 X + x₁ + 50 + x₁ + 51 + x₁ + 52 + x₁ + 53

50 X + 4 x₁ + 206

50 X + 4 [(50 X - 1225) / 50] + 206

50 X + 4 X - 98 + 206

54 X + 108

∴, Average = Sum / No. of terms

                   = (54 X + 108) / 54

                   = X + 2