ITPEC FE Morning April 2021 Question 54
In system development, when the relationship between person-months and the duration (months) is represented in the approximate expression shown below, and the total person-month is 4096, how many months does it take?
Duration = 2.5 × person-months1/3
Explanation
40 months — take the cube root of the person-months, then multiply by 2.5.
- •Cube root: 16 × 16 × 16 = 4096, so 40961/3 = 16
- •Duration: 2.5 × 16 = 40 months
Check: 4,096 person-months over 40 months means an average team of about 102 people.
Answer (b)
Why not others:
- •(a) 16 — the cube root alone, without the factor 2.5
- •(c) 64 — the square root of 4,096 instead of the cube root, without the factor 2.5
- •(d) 160 — the square root multiplied by 2.5, 2.5 × 64: the right factor applied to the wrong root
Key rule: A fractional power is a root: x1/3 is the cube root and x1/2 the square root; duration grows much more slowly than effort.
Project Management · AI-written, may contain errors
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