Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 2)
2.
A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With help of C, they did the job in 4 days only. Then, C alone can do the job in:
Answer: Option
Explanation:
| (A + B + C)'s 1 day's work = | 1 | , |
| 4 |
| A's 1 day's work = | 1 | , |
| 16 |
| B's 1 day's work = | 1 | . |
| 12 |
 C's 1 day's work = |
1 | - |  |
1 | + | 1 |  |
= | |
1 | - | 7 | |
= | 5 | . |
| 4 | 16 | 12 | 4 | 48 | 48 |
| So, C alone can do the work in | 48 | = 9 | 3 | days. |
| 5 | 5 |
Discussion:
224 comments Page 12 of 23.
Lovely said:
1 decade ago
Why take 1/4 in first step?
Jack said:
1 decade ago
B's 1 day's work = 1/12.
Therefore C's 1 day's work = 1-(1+1) = (1 -7) = 5.
4 16 12 4 48 48.
So, C alone can do the work in 48 = 93 days.
Therefore C's 1 day's work = 1-(1+1) = (1 -7) = 5.
4 16 12 4 48 48.
So, C alone can do the work in 48 = 93 days.
Ravikumar said:
1 decade ago
How (1/16+1/20)?
Lokesh said:
1 decade ago
Why C-A+B?
Therefore C's 1 day's work = (1/4)-(1/16+1/20).
Therefore C's 1 day's work = (1/4)-(1/16+1/20).
Phani Kumar said:
1 decade ago
Can explain 5/48 has come?
Ayush said:
1 decade ago
Can anybody explain the basic to know how the 48/5 comes?
Anurag said:
1 decade ago
Can anybody explain LCM method like this?
Lets see this simple method,
LCM of 16 and 12 is 48.
So A and B will finish their work in 3 and 4 hr.
Answer C will finish in 12 hr.
Hence 12-(3+4) = 5 hr.
Hence answer is 48/5.
Lets see this simple method,
LCM of 16 and 12 is 48.
So A and B will finish their work in 3 and 4 hr.
Answer C will finish in 12 hr.
Hence 12-(3+4) = 5 hr.
Hence answer is 48/5.
Mohammed aqib said:
1 decade ago
In equation 5/48 how did 5 arise?
Mahesh sawant said:
1 decade ago
Please explain how come 5/48?
Pundir said:
1 decade ago
All the explanations are really amazing and understandable. But I would like to add a point to the discussion. Why did we do 1/16, 1/12 or 1/4. See there is lot frequency distribution in the values. So to ease our lives we want to compare all this to a benchmark value.
In this case everybody is taking different number of duration's to complete a particular task. So first we want to find out how much work everybody was able to complete in any particular day. Just to make the calculations easier.
And if one can do (1/16)th part of a work in one day, then just by reversing the fraction we can get to know in total how many days he/she will be able to complete the entire task.
Hope this will help.
In this case everybody is taking different number of duration's to complete a particular task. So first we want to find out how much work everybody was able to complete in any particular day. Just to make the calculations easier.
And if one can do (1/16)th part of a work in one day, then just by reversing the fraction we can get to know in total how many days he/she will be able to complete the entire task.
Hope this will help.
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