I think I got confused on what the question was asking, is this an "all weaken except" question? I didn't like the online answer explanation.

For the last five years, the XYZ Courier Company has made regular delivery trips between Town A and Town B. The average time taken by the company’s drivers to drive the round trip between the two towns, excluding the time taken for loading, unloading, and delivery, over that period has been 80 minutes. John, a driver for XYZ, needs to make a personal trip between the two towns; he figures that he should allow approximately 80 minutes for the round trip.

Which of the following, if true, does not call John’s conclusion into question?


A. The route between Town A and Town B has been plagued by increasing congestion over the last five years, as the area's population has doubled during that time.

b. Most of XYZ’s courier vehicles are heavy trucks, for which speed limits are lower than for passenger vehicles.

c. Many of the packages carried by XYZ between Town A and Town B are large, high-security packages, for which the processes of loading, unloading, and delivery can take up to half the length of the trip itself.

d. John will make his personal trip at an hour when XYZ does not make delivery trips.

e. Before a freeway was built between Town A and Town B two years ago, the only routes between the two towns were state highways with multiple traffic lights and reduced-speed downtown zones.

I suppose the confusion is what fulfills as a misconstrued conclusion on John's behalf. Is it that we're supposed to consider an underestimation as a wrong conclusion, or do we consider an overestimation as a wrong conclusion as well.
Here, we have to factor in both.

Option A -> Underestimation. Increased congestion on roads would mean John would take more than 80 mins.

Option B -> Overestimation. This would mean he would be travelling faster than the courier vehicles.

Option D -> Invalid Estimation. This implies that he'd make a trip during non-working hours of XYZ company. So the conclusion that it takes an average of 80 mins for a round trip during those hours is an invalid one.

Option E -> Overestimation. 80 mins is average of 5 years. This option states that for the first 3 years of that period, the average was higher. So currently it is lower.

Option C -> Packing/loading/unloading etc time is irrelevant to John's estimates and conclusion. And hence, the correct choice.

will go with the irrelevant option C and elaboration by angad is gud.

Thanks for the help!

I would agree that this is a weaken except question--good thinking!

_________________
Jamie Nelson
ManhattanGMAT Instructor