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 5 of 7.
Tarun said:
6 years ago
The work completed by A&B in one day is,
1/A + 1/B = 1/30 ---> (1)
(1/A + 1/B) * 20 + 1/A * 20 = 1 ---> (2)
Substitute the value of equation (1) in equation (2),
20/30 + 20/A = 1,
20/A = 10/30,
1/A = 1/60.
So, A alone can finish work in 60 days.
1/A + 1/B = 1/30 ---> (1)
(1/A + 1/B) * 20 + 1/A * 20 = 1 ---> (2)
Substitute the value of equation (1) in equation (2),
20/30 + 20/A = 1,
20/A = 10/30,
1/A = 1/60.
So, A alone can finish work in 60 days.
Srj Jaiswal said:
6 years ago
Hello,
A+b = 60/30 =>2
B=60/20 =>3
60 is total work.
A+b=2,
A+3=2,
A=1.
So, A divided total work.
A=60/1.
= 60ans.
A+b = 60/30 =>2
B=60/20 =>3
60 is total work.
A+b=2,
A+3=2,
A=1.
So, A divided total work.
A=60/1.
= 60ans.
(1)
RaghavendrA naik said:
6 years ago
A and B should take 30 days completely to finish.
And they finished 20 days work.
20/30 work is over.
10/30=1/3 work remaining.
That work completed by 20days by A.
20*3=60 days required.
And they finished 20 days work.
20/30 work is over.
10/30=1/3 work remaining.
That work completed by 20days by A.
20*3=60 days required.
Sap said:
6 years ago
A and B together complete the project in 5 days. A alone can do the project in 8 days. How many days will B alone take to complete the same project? Can anyone solve this?
Prabu said:
6 years ago
A and B together can complete a piece of work in 12 days. They worked together for 5 days and A alone finished the rest of the work in 14 days. An alone can complete the work in?
Ashutosh said:
6 years ago
A and B together can complete a work in 30 day. They started together but after 6
days A left the work and the work is completed by B after 36 more days. A alone can complete
the entire work in how many days?
Please answer fast and answer is 90 btw ssc cpo question with answer that is 90.
days A left the work and the work is completed by B after 36 more days. A alone can complete
the entire work in how many days?
Please answer fast and answer is 90 btw ssc cpo question with answer that is 90.
Anuu said:
6 years ago
Good job @Kaaly.
Bantu Venkatesh said:
6 years ago
Together 1/30*20=2/3.
2parts work completed.
Remaining 1 part 'A'completed in 20days.
1part work 20days.
3 prts --------?.
3 * 20 = 60 days.
2parts work completed.
Remaining 1 part 'A'completed in 20days.
1part work 20days.
3 prts --------?.
3 * 20 = 60 days.
(2)
Himanshu said:
5 years ago
Nice. Thanks all for explaining.
Pankaj khatikkar said:
5 years ago
Can anyone explain this with LCM method?
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