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:

9 1 days
5

9 2 days
5

9 3 days
5

10
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

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 = 9 3 days.
5 5

Discussion:
224 comments Page 9 of 23.

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.

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.

Sunny said:   1 decade ago
How to convert 5/48 = 9*3/5?

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.

Srinivas said:   1 decade ago
C's 1 day work was 5/48. So it can be written as 1/(48/5) and as per the formula if C can do a work in 1/n days then C can complete work in n days which is 48/5. Mixed fraction is written as 9(3/5) = (5*9+3 )/5.

Carlo said:   1 decade ago
1/4 = 1/16 + 1/12 + 1/X.

X = 9.6 days or 9 3/5 days.

Naseer Mohammad said:   1 decade ago
Why you have shown 48/5 instead of 5/48? Any one can help me.

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.

Anusha said:   1 decade ago
I didn't get clearly that how 5/48 is reversed? can anyone help me for better understanding?


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