Multiple choice

Twenty workers can finish a piece of work in 30 days. After how many days should 5 workers leave the job so that the work is completed in 35 days?

  1. 12 days

  2. 15 days

  3. 16 days

  4. 18 days

  5. 20 days

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total work = 20 × 30 = 600 units. After x days, 15 workers work for (35-x) days: 20x + 15(35-x) = 600. Solving: 5x = 75, x = 15. 5 workers should leave after 15 days.