A covered one-fourth of total distance in 2 hours, so 1/2 distance in 4 hours Now B has covered that same distance that A covered in (4 - 2) = 2 hours [Since B started after 2 hrs] And since distances are same So distance covered by A = distance covered by B ⇒ 20 × 4 = x ×2 Therefore, x = 40 km/hr