A supply plenum feeds three branch ducts carrying 300, 450, and 250 CFM respectively. The main trunk must carry at least how much CFM?

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Multiple choice — select the best answer

A1,000 CFM
B450 CFM
C750 CFM
D900 CFM

✓ Correct answer: A. 1,000 CFM The main trunk must carry the sum of all branches: 300 + 450 + 250 = 1,000 CFM. Conservation of mass (continuity equation) requires airflow entering a junction to equal airflow leaving.

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Topic: Airflow & Ductwork

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A supply plenum feeds three branch ducts carrying 300, 450, and 250 CFM respectively. The main trunk must carry at least how much CFM?

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