The distance between any two points P₁(x₁, y₁) and P₂(x₂, y₂) is given by the following formula:

⇒ From the question we have,

⇒ A = (4, p)

⇒ B = (1, 0)

⇒ d = 5

⇒

⇒ Squaring both sides

⇒ 25 = (-3)² + p²

⇒ 25 = 9 + p²

⇒ p² = 25 – 9

⇒ p² = 16

⇒ p = ±4

Therefore the value of p is ±4.