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 7 of 23.
Sonyy said:
1 decade ago
Why you have shown 48/5 instead of 5/48? Anyone can help me.
Sona said:
1 decade ago
Hey I understood they gave answer in fraction form so 5/48 we need not any fraction so its inverse 48/5.
C = 1/4 = 5/48.
C = 4 = 48/5.
C = 1/4 = 5/48.
C = 4 = 48/5.
Anusha said:
1 decade ago
I didn't get clearly that how 5/48 is reversed? can anyone help me for better understanding?
Dumpati Mahesh said:
1 decade ago
@Anusha,
For getting one day work it should be reversed. i.e. 1/(5/48) = 48/5.
For getting one day work it should be reversed. i.e. 1/(5/48) = 48/5.
Dumapti Mahesh said:
1 decade ago
I have another method to solve this:
Suppose the C's work take as z days.
We have the formula that (A+B+C) work = (xyz/(xy+yz+zx)).
Here x=12(A alone work),y=16(B alone work).
=>192z/(192+16z+12z)=4 days(given).
upon simplifying. we get,
48z = 192+28z.
z = 192/20=> 48/5.
Suppose the C's work take as z days.
We have the formula that (A+B+C) work = (xyz/(xy+yz+zx)).
Here x=12(A alone work),y=16(B alone work).
=>192z/(192+16z+12z)=4 days(given).
upon simplifying. we get,
48z = 192+28z.
z = 192/20=> 48/5.
Hasan Ali Tariq said:
1 decade ago
@Carlo.
I think Carlo explain it nicely and simply. The issue of inverse value 5/48 to 48/5.
I think Carlo explain it nicely and simply. The issue of inverse value 5/48 to 48/5.
Chethan k m said:
1 decade ago
How to write 48/5 in the form of 9 3/5?
Jeevi said:
1 decade ago
The 5 is base and 5 table 9*5=45 remain 3 so you should write 9 3/5 are you understand.
Surendra said:
1 decade ago
Why you have shown 48/5 instead of 5/48?
Sagar Malunjkar said:
1 decade ago
@Surendra.
See carefully,
In second last step we have calculated C's 1days work is 5/48.
But our exact question is "C alone can do the job in how much days" so according to formula -
If C's 1 day's work = 1/n, then C can finish the work in n days ie n/1 days.
So that's why 5/48 became 48/5.
See carefully,
In second last step we have calculated C's 1days work is 5/48.
But our exact question is "C alone can do the job in how much days" so according to formula -
If C's 1 day's work = 1/n, then C can finish the work in n days ie n/1 days.
So that's why 5/48 became 48/5.
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