18 persons can do a work in 45 days. They are joined by 12 more persons. In how much time can this work be completed now?
Show answer & explanation
Correct answer: B
Explanation
Total work = 18 × 45 = 810 person-days
Number of new persons = 18 + 12 = 30
Days required = 810 ÷ 30 = 27 days