T3W9 TS Q05 – Selective High School

“An airplane pilot must be able to do mental calculations and remain calm.”

If this is true, which one of these sentences must also be true?

If Peter is not a pilot, he cannot remain calm. If Peter cannot do mental calculations, he cannot be a pilot. If Peter can do mental calculations and remain calm, he must be a pilot. If Peter is not a pilot, he cannot do mental calculations.

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If this is true, which one of these sentences must also be true?