imSKR
Say: GroupA: Airfare 100$ ; other TE 100$ (total people : 100)
Quote:
(D) Overall, people who did not travel by airplane had lower average transportation expenses than people who did.
TE( travel by plane)= 200/100 = 2$
Case1: 100/500 = 0.2$ [GroupB : Other mode 50$; other TE: 50$ ( total people 500) or GroupB : Other mode 20$; other TE: 80$ ( total people 500) or GroupB : Other mode 80$; other TE: 20$ ( total people 500)]
Case2: 200/500 = 0.4$ [GroupB : Other mode 100$; other TE: 100$ ( total people 500) or 50:150 or 150:50]
Case3: 500/500 = 1$ [GroupB : Other mode 250$; other TE: 250$ ( total people 500) or 200:300 or 300:200]
Case4: 1000/500 = 2$ [GroupB : Other mode 500$; other TE: 500$ ( total people 500) or 400:600 or 600:400]
Case 3 and case 4: Doesn't satisfy
Wrong
Quote:
(E) Those who traveled by airplane spent about as much, on average, on other means of transportation as they did on airfare.
Those who traveled by airplane = 100 people spent on average other means of transportation ( 100$) as they did on airfare(100$)
average airfare: 100/100( airfare)= 1
average no-airfare= 100/100 = 1
Same 1:1
correct
Sir , whats wrong in my D and E.
I chose E over D.
What am I missing. I checked above explanations
Doubts for D: why non- airfare expense can not be more than airfare? people who didnt travel by air may have spent more while travelling by train or car . Airfare is not always expensive than other modes of transportation
Doubts for E: Why people considered the amount spent on other modes of travel of group who didnt use air. Option E specifically asks average of people spent on airfare with other modes. Why do we need to consider expensiture o other group whih is not asked for.
Please correct
AndrewN sir
GMATNinjaI think you have lost sight of the passage,
imSKR. You know by now that I recommend a streamlined approach that leans heavily on exactly what the passage says. When you create a scaffolding around a half truth, you still get an incorrect answer. How about we approach these two answer choices by quoting the passage directly?
Quote:
Transportation expenses accounted for a large portion of the total dollar amount spent on trips for pleasure by residents of the United States in 1997, and about half of the total dollar amount spent on the transportation was airfare. However, the large majority of United States residents who took trips for pleasure in 1997 did not travel by airplane but used other means of transportation.
If the statements above are true, which of the following must also be true about United States residents who took trips for pleasure in 1997?
(D) Overall, people who did not travel by airplane had lower average transportation expenses than people who did.
What do we know about
people who did not travel by airplane? The last sentence of the passage tells us that this group represents
the large majority of travelers. Since the first sentence tells us that
about half of the total dollar amount spent on the transportation was airfare, we can deduce that within that
other half of transportation expenses would lie the total dollar amount spent by our target group, those who did not travel by airplane. Stitched together, we can say with certainty that more of one group of travelers spent no more money on transportation expenses than did another group, even if the transportation expenses were the same on the whole. Finally, when you divide either the same amount or a lesser amount by a greater number (of travelers, in this case), the average will always be lower. Thus, we cannot argue against (D).
Quote:
(E) Those who traveled by airplane spent about as much, on average, on other means of transportation as they did on airfare.
Where do we get any information in the passage about
those who traveled by airplane also spending on
other means of transportation? Not in the first sentence, and not in the second either. So, in short, we cannot speculate on how much this group of people may have spent on transportation outside of airfare. There is nothing to lean on in the passage, the opposite of what we want in a
must be true answer. This should be an easy elimination.
I hope you will take the time to let these points sink in. Sometimes when you want something to be true, you (the general you) close your mind to other possibilities and forget to seek out evidence to support your idea.
Thank you for thinking to ask me about this one.
- Andrew