P + t = 140
t = p - 4 or p - t = 4
answer is A first one
Mean:
E[Y] = E[3X₁ + X₂]
E[Y] = 3 E[X₁] + E[X₂]
E[Y] = 3µ + µ
E[Y] = 4µ
Variance:
Var[Y] = Var[3X₁ + X₂]
Var[Y] = 3² Var[X₁] + 2 Covar[X₁, X₂] + 1² Var[X₂]
(the covariance is 0 since X₁ and X₂ are independent)
Var[Y] = 9 Var[X₁] + Var[X₂]
Var[Y] = 9σ² + σ²
Var[Y] = 10σ²
Answer:
see explanation
Step-by-step explanation:
The perimeter is the length of all the sides in the figure.
The arc of the semi- circle is included in this.
length of arc =
πd ← d is the diameter
here d = 8, hence
arc =
π × 8 = 4π ← exact length
Perimeter = 10 + 8 + 10 + 4π ≈ 40.57 in ( nearest hundredth )