Subject: General Aptitude · Chapter: Time and Work · Exam: · Marks: · Difficulty:
A is 50\% as efficient as B. C does half of the work done by A and B together. If C alone does the work in 40 days, then A, B and C together can do the work in:
(a)$13 \frac{1}{3}$ days
(b)15 days
(c)20 days
(d)30 days
Answer
Answer (as printed): A
Explanation
(A’s 1 day’s work) : (B’s 1 day’s work) . = 150 : 100 = 3 : 2. Let A’s and B’s 1 day’s work be 3x and 2x respectively. 3x + 2x 5x Then, C’s 1 day’s work = = . 2 2 ∴ 5x = 1 1 2 or x = × = 1 . 2 40 40 5 100 3 1 A’s 1 day’s work = ; B’s 1 day’s work = ; 100 50 1 C’s 1 day’s work = . 40 3 1 1 15 3 (A + B + C)’s 1 day’s work = + + = = . 100 50 40 200 40 40 1 So, A, B and C together can do the work in = 13 days. 3 3
Explanation as extracted from the printed page; notation may be imperfect.