Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 13)
13.
A and B can together finish a work 30 days. They worked together for 20 days and then B left. After another 20 days, A finished the remaining work. In how many days A alone can finish the work?
Answer: Option
Explanation:
| (A + B)'s 20 day's work = |  |
1 | x 20 |  |
= | 2 | . |
| 30 | 3 |
| Remaining work = | |
1 - | 2 | |
= | 1 | . |
| 3 | 3 |
| Now, | 1 | work is done by A in 20 days. |
| 3 |
Therefore, the whole work will be done by A in (20 x 3) = 60 days.
Discussion:
63 comments Page 7 of 7.
Anitha said:
2 years ago
A + B = 1/30
B only work 20 days after leaving;
B=1/20,
A+1/20 = 1/30
A = 1/20-1/30
A = 30-20/600
A = 10/600
A = 1/60
So, A Worked alone 60 days.
B only work 20 days after leaving;
B=1/20,
A+1/20 = 1/30
A = 1/20-1/30
A = 30-20/600
A = 10/600
A = 1/60
So, A Worked alone 60 days.
(44)
SamDon Sk said:
2 years ago
Assume painting a room A + B can complete in 30 days.
But they work for only 20 days and b left till now they have painted most of the room.
The remaining days left they can do work together is 10 days.
But A worked for 20 days to complete that 10 days of work MEANS.
A had worked DOUBLE days as they can work together.
So, A can alone can complete the work is DOUBLE of together work that is 30 * 2 = 60.
But they work for only 20 days and b left till now they have painted most of the room.
The remaining days left they can do work together is 10 days.
But A worked for 20 days to complete that 10 days of work MEANS.
A had worked DOUBLE days as they can work together.
So, A can alone can complete the work is DOUBLE of together work that is 30 * 2 = 60.
(28)
Abinesh said:
7 months ago
A + B = 30 days
Then A + B works for 20 days.
This shows that they have completed 2/3 works.
Now 1/3 of the work is done by A in 20 days.
So, 1/3 * 1/20,
= 60 days.
Then A + B works for 20 days.
This shows that they have completed 2/3 works.
Now 1/3 of the work is done by A in 20 days.
So, 1/3 * 1/20,
= 60 days.
(4)
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