d = y, s = 6 m/s (The Man & Plane Mirror)d – δy, s = (5 &ndash ;6) m/s (The Man and Image)d2 ÷ s1 = d2 ÷ s2, y ÷ 6 = 2y ÷ s + 6Y (s + 6) = 2y × 6s + 6 = 12So = 12 – 6 = 6Since S + 6 = 0Then, S = 6 (substitute the value of S i.e S = 6)Into S + 6 = 0∴So = S + 6 = 6 + 6 = 12 m/s∴ S = 12 m/s