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:
226 comments Page 18 of 23.
Shakir said:
1 decade ago
We know a formula that,
If A do a work in X days, B do a work in Y days and C do a work in Z days.
Then all of three can do the same work in = XYZ/(XY+YZ+ZX).
Then,
According to question,
A do a work in 16 days,B do the same work in 12 days and let C do the same work in Days
Then we can write as,
(16*12*x)/(16*12+12x+16x) = 4.
And solve it.
If A do a work in X days, B do a work in Y days and C do a work in Z days.
Then all of three can do the same work in = XYZ/(XY+YZ+ZX).
Then,
According to question,
A do a work in 16 days,B do the same work in 12 days and let C do the same work in Days
Then we can write as,
(16*12*x)/(16*12+12x+16x) = 4.
And solve it.
Leena said:
1 decade ago
One day's work is 5/48.
But we want number of days that 'C' alone can do, so 48/5 days.
But we want number of days that 'C' alone can do, so 48/5 days.
Manoj Kumar said:
1 decade ago
Why you have shown in the last fraction 48/5 in where the result has come out 5/48? Please explain it.
Ashim Ray said:
1 decade ago
Why you have shown in the last fraction 48/5 in where the result has come out 5/48?
Sonu said:
1 decade ago
Why do we take fraction and add and subtract everything?
Srinivas said:
1 decade ago
If I go for another way as follows:
A B and C can do work in 4days.
A alone 16 days.
B alone 12 days.
C alone ?... Lets assume it as X.
Let me apply this formula
Work done by A B and C put together i.e 4= (16*12*X)/(16+12+X) //(A*B*C)/(A+B+C).
28+X=48X.
28=47X.
X=28/47.
According To you Answer is Wrong How is it. Please Reply me As soon As possible.
A B and C can do work in 4days.
A alone 16 days.
B alone 12 days.
C alone ?... Lets assume it as X.
Let me apply this formula
Work done by A B and C put together i.e 4= (16*12*X)/(16+12+X) //(A*B*C)/(A+B+C).
28+X=48X.
28=47X.
X=28/47.
According To you Answer is Wrong How is it. Please Reply me As soon As possible.
Sudha said:
1 decade ago
At the end of explanation,
C's 1 day work is 5/48 I calculated up to to this but how it comes work in 48/5 days.
Because acc. to formula if A's 1 day work is 1/n' then A can finish work in n' days.
Means only it comes 48. I am just confuse. please explain me.
C's 1 day work is 5/48 I calculated up to to this but how it comes work in 48/5 days.
Because acc. to formula if A's 1 day work is 1/n' then A can finish work in n' days.
Means only it comes 48. I am just confuse. please explain me.
Twinkle said:
1 decade ago
A+B+C=1/4.
[1/16]+[1/12]+C=[1/4].
C=0.1041.
THEREFORE, 1/0.1041=48/5.
i.e: 9*3/5.
[1/16]+[1/12]+C=[1/4].
C=0.1041.
THEREFORE, 1/0.1041=48/5.
i.e: 9*3/5.
Ajay jabalpur said:
1 decade ago
@Hiren.
If A's one day work = 1/n, then A can finish the work in n/1 days.
Similarly,
C's one day work is 5/48, then C can finish the work in 48/5 days.
If A's one day work = 1/n, then A can finish the work in n/1 days.
Similarly,
C's one day work is 5/48, then C can finish the work in 48/5 days.
Shiyamala said:
1 decade ago
A=1/16;
B=1/12;
A+B=[1/16+1/12]
=[16+12/192]{1/16*12/12=16/192;1/12*16/16=16/192)
=28/192
=7/48 {4*7=28; 48*4=192)
C-[A+B]=1/4-7/48 {1/4*12/12=12/48)
=12-7/48
=5/48
but c work alone.so,48/5=9*3/5
B=1/12;
A+B=[1/16+1/12]
=[16+12/192]{1/16*12/12=16/192;1/12*16/16=16/192)
=28/192
=7/48 {4*7=28; 48*4=192)
C-[A+B]=1/4-7/48 {1/4*12/12=12/48)
=12-7/48
=5/48
but c work alone.so,48/5=9*3/5
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