AbdurRakib
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?
(A) Most of those who traveled by airplane did so because the airfare to their destination was lower than the cost of other available means of transportation.
(B) Most of those who traveled by airplane did so because other means of transportation to their destinations were unavailable.
(C) Per mile traveled, those who traveled by airplane tended to spend more on transportation to their destination than did those who used other means of transportation.
(D) Overall, people who did not travel by airplane had lower average transportation expenses than people who did.
(E) Those who traveled by airplane spent about as much, on average, on other means of transportation as they did on airfare.
This is a must be true inference question. We need to select what must be true.
Premises:About 50% of the total dollar amount spent on the transportation was airfare.
But the large majority of people did not travel by airplane but used other means of transportation.
So overall, 50% of total transport cost was airfare. So say total overall transport cost was $1000 so $500 was airfare. (small numbers for ease). Rest $500 was ship, car, train etc all combined.
But say out of total 100 people who travelled, 80 people (large majority) did not take the plane at all. Only 20 people took the plane (and could have used other means of transport too for local travel)
Then it seems that the total cost of transport for these 20 people was $500 or a bit more than $500 (airfare + other means if used) while for all other 80 people, the cost of transport was less than $500.
The average for plane users was about $25 per person (may be even a bit more) and avg for non plane users was about $6.
(D) Overall, people who did not travel by airplane had lower average transportation expenses than people who did.Hence (D) works.
(A) Most of those who traveled by airplane did so because the airfare to their destination was lower than the cost of other available means of transportation.If anything, it seems that the airfare is higher than fares of most other methods.
(B) Most of those who traveled by airplane did so because other means of transportation to their destinations were unavailable.We don't know why people took flights. It could be that nothing else was available or because they wanted to save time or whatever other reason. We don't know people's reason.
(C) Per mile traveled, those who traveled by airplane tended to spend more on transportation to their destination than did those who used other means of transportation.The statement says "per mile travelled" and that makes all the difference. Perhaps flights are expensive but normally they were taken for long distances which means that per mile, the cost of flight turned out to be lower. We cannot say for sure that those who took planes spent more per mile.
Say A took a plane for a distance of 2000 miles and paid $100 toward airfare. Per mile travelled, A paid $.05.
B did not take a plane and travelled only 100 miles and paid $10 toward train fare. Per mile travelled, B paid $.1.
All we can say is that people who travelled by plane paid more in total.
(E) Those who traveled by airplane spent about as much, on average, on other means of transportation as they did on airfare.This may or may not be true. We cannot say. It is possible that these people did spend as much on other means also but we cannot say that they certainly did.
Answer (D)