Subject: General Aptitude · Chapter: Time and Work · Exam: · Marks: · Difficulty:
To do a piece of work, B takes 3 times as long as A and C together and C twice as long as A and B together. If A, B and C together can complete the work in 10 days, how long would A take alone to complete it?
(a)24 days
(b)30 days
(c)36 days
(d)40 days
Answer
Answer (as printed): A
Explanation
3 (B’s 1 day’s work) = (A + C)’s 1 day’s work ⇒ 4 (B’s 1 day’s work) = (A + B + C)’s 1 day’s work 1 1 1 ⇒ B’s 1 day’s work = × = . 4 10 40 2 (C’s 1 day’s work) = (A + B)’s 1 day’s work ⇒ 3 (C’s 1 day’s work) = (A + B + C)’s 1 day’s work 1 1 1 ⇒ C’s 1 day’s work = × = . 3 10 30 \ A’s 1 day’s work = (A + B + C)’s 1 day’s work – (B + C)’s 1 day’s work 1 1 1 1 7 5 1 = – + = – = = . 10 40 30 10 120 120 24 Hence, A alone would take 24 days to complete the work.
Explanation as extracted from the printed page; notation may be imperfect.