Original question written by FE Exam AI Prep from the public FE Civil exam specification. Before release, a solver model re-derived the answer twice from the question alone, without its answer key, and a critic model checked the result, and the arithmetic was re-run as an executable calculation. No licensed engineer reviews these questions. It is not an NCEES question and does not come from any NCEES practice exam. FE Exam AI Prep is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCEES.
Activity Duration from Production Rate: FE Civil practice problem 6
For the Red River detention pond retrofit, a materials reviewer preparing a resident-engineer calculation check schedules 720 units of work with 4 crews, each producing 45 units/day. What duration is required?
- A4.00 days
- B2.33 days
- C2.95 days
- D4.51 days
Show the answer and worked solution
Answer: A — 4.00 days
Worked solution
- Step 1. Divide total work by combined production
duration = work/(crews x production)
duration = 720/(4 x 45) = 4 days
Why the other choices are wrong
- Choice B
- No single clean misstep in dividing the total quantity by 4 crews times 45 units per day produces this moderately high figure; the direct division returns a smaller duration that matches the stated crew and production data.
- Choice C
- Dividing 720 units by the combined output of 4 crews at 45 units per day gives a larger duration than this total, and no single obvious substitution error explains why this figure runs low, so the bigger value is the supported result.
- Choice D
- This duration sits well above what 720 divided by 4 times 45 actually returns, and the size of the gap does not trace back to one clean substitution error, so the smaller result from the direct division should be treated as correct.