Self-study
The airport's runways are too close to each other to allow simultaneous use of adjacent runways when visibility is poor, so the airport allows only 30 planes an hour to land in poor weather; in good weather 60 planes an hour are allowed to land. ███████ ███████ █████████ ██████ ████ ████████ ███ ███████ ███████ ███████ ███████
Summary
Simultaneous use of adjacent runways at the airport is not allowed when visibility is poor because the runways are too close together. The airport allows 30 planes per hour to land when weather is poor. 60 planes can land per hour in good weather. Airline schedules assume good weather, so bad weather creates delays.
Strongly Supported Conclusions
One cause of delays would go away if the adjacent runways were not too close together or if the weather were always good. Airline schedules assume that 30 planes per hour can land at the airport.
22.
Which one of the following ██ ████ ████████ █████████ ██ ███ ███████████ ██████
a
In poor weather, ████ ████ ██ ████ ██████ ███ ███████ ██ ████ ████ ████ ██ ███ ███ ██████ ██ ███ ███████ ██ ███ ███████ ██ ████ ██ ██ ██ ████ ████████
This is unsupported because each individual runway may support the same number of airplanes regardless of the weather. When weather is bad, however, only one runway can be used at a time.
b
When the weather ██ ███ ███████ ██ ████ ██ ██ ██████ ████ █████ ███ ██████ ███████ ██ ███ ████████ ███████ ██ ███ █████ █████
This is unsupported because although both adjacent runways can be used at the same time when weather is good, we don’t know that planes are likely landing at any given time. We only know that both lanes are open, not that they are likely to have planes at any moment.
c
If any two ██ ███ █████████ ███████ ███ ████ ███████████████ ███████ ██████ ███████
This is unsupported because serious delays are a product of one of the adjacent runways being closed off when weather is bad, not because two runways are being used.
d
Airlines using the ███████ ████ █████ █████████ ██ ███ ██████████ ████ ████ ████ ██ ██████ ██ ████ ████ ██ ███████ ██ ████ ██ ███ ████████
This is strongly supported because we know that airlines base their assumption on good weather, and in good weather, more than 30 planes are allowed to land per hour.
e
In good weather, █████ ███ ███ ██ ███ █████████ ███████ ███████ ██ ███ ████████
This is unsupported because we only know that bad weather is one of the causes of delays. There may be several other causes of delays even when the weather is good that we aren’t aware of from the stimulus.