Explanation : First statement is not sufficient to answer the question because the speed of the second half of the distance is not given here but statement II can answer as
information to calculate average speed = distance/time
is given in the statement.
Explanation : Time taken by B to reach destination = 350/50 =
If A has a head start of 1 hour then the distance
travelled by A when B reaches the destination
= 40 × (7 + 1) = 320 km
Hence, A has to still travel 30 km while B has
reached the destination.