Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 28)
28.
X can do a piece of work in 40 days. He works at it for 8 days and then Y finished it in 16 days. How long will they together take to complete the work?
Answer: Option
Explanation:
| Work done by X in 8 days = |  |
1 | x 8 |  |
= | 1 | . |
| 40 | 5 |
| Remaining work = | |
1 - | 1 | |
= | 4 | . |
| 5 | 5 |
| Now, | 4 | work is done by Y in 16 days. |
| 5 |
| Whole work will be done by Y in | |
16 x | 5 | |
= 20 days. |
| 4 |
 X's 1 day's work = |
1 | , Y's 1 day's work = | 1 | . |
| 40 | 20 |
| (X + Y)'s 1 day's work = | |
1 | + | 1 | |
= | 3 | . |
| 40 | 20 | 40 |
| Hence, X and Y will together complete the work in | |
40 | |
= 13 | 1 | days. |
| 3 | 3 |
Discussion:
33 comments Page 2 of 4.
Atul said:
6 years ago
Wonderful explanation, thanks @Mohit.
(1)
Sutha said:
7 years ago
How 4/5 becomes into 5/4. Please clarify it.
Prashant singh said:
7 years ago
How 3/40 is converted to 40/3?
Ashis said:
7 years ago
Thanks for the solution @Mohit.
Manu said:
8 years ago
The total work has done in two parts.
Y completed only 4/5 part of work. another part is done by X.
So work done by Y one day is 1/total work
= 5/4.
But, no need to get confused. simply solve as;
Y completed 4/5 part of work in 16 days.
one day's work is work/days.
divide 4/5 by 16.
We get the answer 1/20 directly.
Y completed only 4/5 part of work. another part is done by X.
So work done by Y one day is 1/total work
= 5/4.
But, no need to get confused. simply solve as;
Y completed 4/5 part of work in 16 days.
one day's work is work/days.
divide 4/5 by 16.
We get the answer 1/20 directly.
(2)
Mohit said:
9 years ago
First LCM of 40 is 40,
x can work 40 days,
work = 1 unit,
8*1 = 8,
remaining work 40 - 8 = 32,
Y finished it in 16 days then = 32/16 = 2,
x+y = 1+2 = 3,
40/3 answer.
x can work 40 days,
work = 1 unit,
8*1 = 8,
remaining work 40 - 8 = 32,
Y finished it in 16 days then = 32/16 = 2,
x+y = 1+2 = 3,
40/3 answer.
(7)
Pooka said:
9 years ago
Thank you @Parthasarathy.
P.muthukumar said:
9 years ago
What is the reason for converting 4/5 to 5/4?
Gobind Mandal said:
9 years ago
Why did you convert 4/5 to 5/4?
Makvana Disha said:
9 years ago
We are also do this,
x = 40days = 100%
For 8 days = ? (20%) so, 80% works remaining. That is done by y in 16 days.
80% = 16days
100% = ? (20days)
(x + y)'s 1 day work = (1/40) + (1/20).
= (3/40).
= (40/3) = 13*1/3.
x = 40days = 100%
For 8 days = ? (20%) so, 80% works remaining. That is done by y in 16 days.
80% = 16days
100% = ? (20days)
(x + y)'s 1 day work = (1/40) + (1/20).
= (3/40).
= (40/3) = 13*1/3.
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