Subject: General Aptitude · Chapter: Time and Work · Exam: 2007 · Marks: · Difficulty:
A can complete a piece of work in 10 days, B in 15 days and C in 20 days. A and C worked together for 2 days and then A was replaced by B. In how many days, altogether, was the work completed?
(a)6
(b)8
(c)10
(d)12
Answer
Answer (as printed): B
Explanation
(A + C)’s 1 day’s work = + = . 10 20 20 3 3 (A + C)’s 2 days’ work = × 2 = . 20 10 3 7 Remaining work = 1 – = . 10 10 1 1 7 (B + C)’s 1 day’s work = + = . 15 20 60 7 work is done by B and C in 1 day. 60 7 60 7 work will be done by B and C in × = 6 days. 10 7 10 Hence, total time taken = (2 + 6) days = 8 days. 1 1 1 37
Explanation as extracted from the printed page; notation may be imperfect.