KASSALMD wrote:

It should be C.

Statement 2: Let the speed for the 1st half distance d be S1 and that for the 2nd half distance d be S2.

S1 = d/t and S2 = d/2t where t is the time taken to travel each half. Therefore total time taken = 3t.

3t=4 hrs. t = 4/3hrs.

From St. 1 we know that the bus travels 100 miles in 2 hrs.

For 1+1/3 hr the bus travels at a certain speed and for 2-4/3=2/3 hrs, the bus travels at 1/2 that speed (by St. 2).

The bus covers distance d in 4/3 hrs. It would cover d/2 in the next 4/3 hrs.Therefore it would cover d/4 in the next 2/3 hrs. Therefore, total distance covered = d + d/4 = 5d/4 = 100

Hence d = 100*4/5 = 80 miles. Therefore, total distance = 80 + 80 = 160 miles and ave. speed = 160/4 = 40 mph

the statement in blue is ok

but i dont agree with the statement in red

suppose that he travels d/6 or d/8 etc etc in the next 4/3 hrs and makes up for it in the next 4/3 hrs so that his avg speed for 8/3 hrs is d/2...then?

see, the point here is that his avg speed for 8/3 time of the journy is s/2.

there are so many ways to achieve it.

what you have considered is ok, BUT ITS NOT THE ONLY POSSIBLITY.There are other ways also of achieving it.