Multiple choice

Twelve men can complete a work in $8$ days. Three days after started the work, $3$ more men joined them. In how many days will all of them together complete the remaining work ?

  1. $2$ day
  2. $4$ day
  3. $5$ day
  4. $6$ day
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total work = 12 * 8 = 96 man-days. Work done in 3 days = 12 * 3 = 36 man-days. Remaining work = 96 - 36 = 60 man-days. New number of men = 12 + 3 = 15. Days to finish = 60 / 15 = 4 days.

AI explanation

Assume the total work is the least common multiple of the days and men, which is 96 man-days, meaning 12 men complete 12 units daily. After 12 men work for 3 days, they complete 36 units of work, leaving 60 units. When 3 more men join, the new team of 15 men completes 15 units daily, so the remaining 60 units are finished in 60 divided by 15, which is 4 days.