Two persons A and B finish a work in 10 days. A is twice as efficient as B.…
2025
Two persons A and B finish a work in 10 days. A is twice as efficient as B. How many days A will take to finish the work, if he has to do it alone?
- A.
8 days
- B.
12 days
- C.
15 days
- D.
18 days
Attempted by 2 students.
Show answer & explanation
Correct answer: C
Let B's efficiency be x units/day. Since A is twice as efficient, A's efficiency is 2x units/day. Together, their combined efficiency is x + 2x = 3x units/day. They complete the work in 10 days, so total work is 3x * 10 = 30x units. To find the time A takes alone, divide total work by A's efficiency: 30x / 2x = 15 days.