Until 1985 all commercial airlines completely replenished the cabin air in planes in flight once every 30 minutes. Since then the rate has been once every hour. The less frequently cabin air is replenished in a plane in flight, the higher the level of carbon dioxide in that plane and the easier it is for airborne illnesses to be spread.

Which one of the following is most strongly supported by the information above?

A) In 1985 there was a loosening of regulations concerning cabin air in commercial airline flights.
B) People who fly today are more likely to contract airborne illnesses than were people who flew prior to 1985.
C) Low levels of carbon dioxide in cabin air make it impossible for airborne illnessess to spread.
D) In 1980 the rate at which the cabin air was replenished in commerical airlines was sufficent to protect passengers from the effects of carbon dioxide buildup
E) In 1980 the level of carbon dioxide in the cabin air on a two-hour commercial airline flight was lower than it is today on a similar flight.

E is wrong. It has to be B.

in E, in a 2 hour flight, the level of CO will be same because it is replenished every hour hour or 1 hour.

B can be inferred.

The statement says

"The less frequently cabin air is replenished in a plane in flight, the higher the level of carbon dioxide"


I think what it means is that the CO will remain in the plane even if the air is replenished every 5 minutes. The argument says "the higher the level" It does not say that the replenishment will clear the air of CO.

I do not like B because it is very generic.

I guess this is close.

This is inference question from the evidence, fact given:

B) People who fly today are more likely to contract airborne illnesses than were people who flew prior to 1985.

B assumes that the cause of "airborne illnesses" is only through "carbon dioxide". That is, there might be other reasons for contracting "airborne illnesses" in flight before 1885 OR todays airlines may be employing other measures to counter the spread of airborne illnesses due to increased level of CO2.


E. This is a fact which can be infered (as PR says dont go too far on inferences) easily from the argument(The less frequently cabin air is replenished in a plane in flight, the higher the level of carbon dioxide in that plane).

B is a strong answer but we cannot necessarily infer it. There may be several factors that may be required to evaluate this option. How much CO2. How long does the person needs to get exposed. With some more of this info this may be inferred but not for sure in it's current state.

Premises
1) Until 1985, airlines replenish cabin air once every 30 mins
2) since 1985, airlines replenish cabin air once evey hour
3) less frequent cabin air is replenish -> higher level of co2 in the plane
4) high level of co2 -> easier for airborne illness to spread

A) In 1985 there was a loosening of regulations concerning cabin air in commercial airline flights.
- not supported for in the passage

B) People who fly today are more likely to contract airborne illnesses than were people who flew prior to 1985.
- Can we really tell that from the statments? Which premise supports allows you to confidently say "yes, people today are weaker and more prone to airborne illness)

C) Low levels of carbon dioxide in cabin air make it impossible for airborne illnessess to spread.
- can't tell if it becomes impossible

D) In 1980 the rate at which the cabin air was replenished in commerical airlines was sufficent to protect passengers from the effects of carbon dioxide buildup
- again, we don't know from the passage if it's sufficient.

E) In 1980 the level of carbon dioxide in the cabin air on a two-hour commercial airline flight was lower than it is today on a similar flight.
- I go with this. On a 2 hr flight, pre 1985 would see the cabin air replenished 4 times, while post 1985, the cabin air would be replenished just 2 times. Based on the statement, the less frequent cabin air is replenished, the higher the level of of co2 in the plane. So since cabin air is replenished more frequently in 1980 than post 1985, then level of co2 in cabin air in 1980 woul be lower.