Logical Reasoning

PT117 · S3 · Q18 Until 1985 all commercial airlines

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Until 1985 all commercial airlines completely replenished the cabin air in planes in flight once every 30 minutes.

Information

Pre-1985: replenished air once every 30 min Post-1985: replenish air once every 60 min

The less frequently cabin air is replenished, the higher the level of CO2 in the plane and the easier it is for airborne illnesses to be spread.

Evaluate

Jeez, I hope airline went back to the pre-1985 standard during the era of COVID.

Here, the information establishes a difference between pre/post 1985, and then we get a rule we can apply to that difference.

Goal

It sounds like pre-1985: less CO2, less chance of airborne illness spreading post-1985: more CO2, more chance of airborne illness spreading

18.

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

  1. In 1985 there was a

    Unsupported Causal Speculation

    We don't know why the rate of replenishing changed. It might be because of regulatory changes, but that's just as supportable as any other hypothesis (f.e. the airlines wanted to save money)

    5% picked this

  2. People who fly today are

    Less Provable than Correct Answer

    This is a very tempting answer, because it goes along with the gist of what we were told about air in the cabin, but it's not a must be true. There are more factors than just air replenishment that can affect likelihood of contracting an airborne illness. Has the average health of passengers changed? Do passengers wear masks more than they used to? Are passengers less likely to fly with germ-ridden children than before? If there weren't a rock-solid provable answer available, then we would certainly pick this.

    25% picked this

  3. Low levels of carbon dioxide

    Too Strong: impossible

    We know that lower levels of CO2 make it harder for airborne illness to spread, but we can't do this Relative vs. Absolute switch and say, when there's low CO2, there's zero risk of spreading airborne illness.

    1% picked this

  4. In 1980 the rate at

    Out of Scope

    Out of Scope: effects of CO2 buildup The passage never discusses "the effects of CO2 buildup". We know one effect of CO2 buildup (easier for airborne illnesses to spread), but there maybe others as well (foggy thinking, fatigue). We don't know if the pre-1985 replenishment rate suppressed CO2 buildup so much that passengers were protected from all of its possible effects. We wouldn't even say that pre-1985 passengers were protected from airborne illnesses; we would just say they were better-protected than in post-1985.

    5% picked this

  5. Correct

    In 1980 the level of

    Why this is right

    On a two hour flight in 1980, the air would be replenished at least 3 times 30 mins in, 60 mins in, 90 mins in On a two hour flight today, the air would be replenished 1 time 60 mins in We have a rule that says "the less frequently it's replenished, the higher the level of CO2 in the plane". So that means that a two hour flight today would have a higher level of CO2 than would have a two hour flight in 1980. (you could say it's also replenished at the 2 hour mark, when the flight is over, but that would still mean 4 replenishments for 1980 and 2 replenishments for today)

    Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.

    64% picked this

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