Multiple choice

Some carpenters promised to complete a work in 20 days. When the work was started, 8 of them were absent, and the remaining completed the work in 40 days. What was the original number of carpenters?

  1. 18

  2. 12

  3. 10

  4. 16
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let original number of carpenters be x. Work = x * 20. After 8 left, (x-8) * 40 = work. So 20x = 40(x-8). 20x = 40x - 320. 20x = 320, x = 16.

AI explanation

Let the original number of carpenters be x, meaning their total work can be expressed as 20x man-days. Since 8 were absent, the remaining x minus 8 carpenters completed the same work in 40 days, giving the equation 40 times (x minus 8) equals 20x. Expanding and solving gives 40x minus 320 equals 20x, which simplifies to 20x equals 320. Therefore, the original number of carpenters was 16.

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