A and B can complete a piece of work in 20 days and 30 days respectively. If they work on alternate days starting with B, in how many days will the work be finished? MCQ with Answer and Explanation
A and B can complete a piece of work in 20 days and 30 days respectively. If they work on alternate days starting with B, in how many days will the work be finished?
A. 24 days
B. 23 days
C. 26 days
D. 25 days
Answer: Option A
Solution (By JKSSB Mock Tests)
Total work = LCM(20, 30) = 60 units. Efficiency of A = 3, B = 2. In 2 days (B then A), work completed = 2 + 3 = 5 units. Time taken to complete 60 units = (60 / 5) * 2 = 24 days.
A is twice as efficient as B, and C is thrice as efficient as B. If they working together can finish a work in 5 days, in how many days can A alone finish it?
Explanation:
Let efficiency of B = 1. Then efficiency of A = 2, and efficiency of C = 3. Combined efficiency = 1 + 2 + 3 = 6. Total work = 5 * 6 = 30 units. Time taken by A alone = 30 / 2 = 15 days.
No comments yet. Be the first to start the discussion!