A and B can do a job in 12 days and 16 days respectively. Both work together for 3 days and then A leaves. How long will B take to complete the remaining work? MCQ with Answer and Explanation
A and B can do a job in 12 days and 16 days respectively. Both work together for 3 days and then A leaves. How long will B take to complete the remaining work?
A. 9 days
B. 8 days
C. 7 days
D. 10 days
Answer: Option A
Solution (By JKSSB Mock Tests)
Total work = LCM(12, 16) = 48 units. Efficiency of A = 4, B = 3. Combined efficiency = 7 units/day. In 3 days, work completed = 7 * 3 = 21 units. Remaining work = 48 - 21 = 27 units. Time taken by B for remaining work = 27 / 3 = 9 days.
Explanation:
Let efficiency of C = 1. Then efficiency of B = 2 and efficiency of A = 4. Combined efficiency of A and B = 4 + 2 = 6. Total work = 4 * 6 = 24 units. Time taken by C alone = 24 / 1 = 24 days.
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