ITPEC IP October 2025 Question 51
When the system development activities are carried out, a plan is set up to complete the activities in 20 days by six (6) members having the same productivity. However, the plan is changed to have the activities finished in 15 days, and new members are added. When the productivity of the new members is half of the initially planned members, what is the minimum number of new members necessary for finishing the activities in 15 days?
Explanation
4 new members — measure the work in person-days of an original member, then fill the shortfall at half productivity.
- •Total work: 6 × 20 = 120 person-days
- •Done by the original six in 15 days: 6 × 15 = 90 person-days
- •Shortfall: 120 − 90 = 30 person-days
- •One new member in 15 days: 15 × 0.5 = 7.5 person-days
- •New members needed: 30 ÷ 7.5 = 4
Check: 4 new members equal 2 original members, and 8 × 15 = 120.
Answer (c)
Why not others:
- •(b) 2 — the number of full-productivity members needed, 30 ÷ 15 = 2, forgetting that new members work at half speed
- •(a) 1 — halves those 2 members instead of doubling them; 1 new member adds only 7.5 person-days
- •(d) 6 — would add 45 person-days, enough but not the minimum
Key rule: Convert all work into one unit (person-days at a reference productivity); a member at half productivity counts as half a person, so twice as many are needed.
Project Management · AI-written, may contain errors
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