coding task takes 60 hours. If 3 programmers start and a 4th joins after 10 hours, how long will it take?
Correct answer: B. 20
- A. 18
- B. 20
- C. 22
- D. 24
Explanation
Initially, 3 programmers work for 10 hours, completing 30 hours of work. When the 4th programmer joins, the new effective work rate becomes 4 programmers. There are 30 hours of work remaining, and at a rate of 4 programmers, it takes 7.5 hours to complete. Since work is typically considered in whole hours, we round up, leading to a total of 20 hours to complete the task. Option B is correct. Option A underestimates the time by failing to account for the work rate after the 4th programmer joins. Options C and D overestimate the time by not accurately calculating the reduced time needed with the additional programmer.
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