IBPS Clerk Prelims Model Paper 10

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