A can finish a work in 18 days and B can do the same work in half the time taken by A. Then, working together, what part of the same work can they finish in a day? MCQ with Answer and Explanation
A can finish a work in 18 days and B can do the same work in half the time taken by A. Then, working together, what part of the same work can they finish in a day?
A. 1/4
B. 1/6
C. 2/5
D. 1/9
Answer: Option B
Solution (By JKSSB Mock Tests)
Time taken by A = 18 days, so B takes 9 days. Efficiency of A = 1/18, B = 1/9. Together in one day = 1/18 + 1/9 = 3/18 = 1/6.
A, B and C can do a piece of work in 24, 30 and 40 days respectively. They start together but C leaves 4 days before the completion of the work. In how many days was the work completed?
Explanation:
Total work = LCM(24, 30, 40) = 120 units. Efficiency of A = 5, B = 4, C = 3. Let the total number of days be x. A and B work for x days, while C works for (x - 4) days. 5x + 4x + 3(x - 4) = 120 => 12x - 12 = 120 => 12x = 132 => x = 11 days.
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