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:
227 comments Page 14 of 23.

Soumya said:   1 decade ago
@Deepika.

C's 1 day work is 5/48.
Here we require C's total work.

Total work should be taken as '1'.

So, 1 day work i.e,5/48*number of days used to complete the work(unknown, so take it as 'x') = total work 1.

Simply, 5/48*x = 1.
5x = 48.
x = 48/5.

So C's total work is 48/5.

Deepika said:   1 decade ago
How is last step is taken 5/48 is reversed to 48/5?
(1)

Suresh said:   1 decade ago
LCM of 4 & 48 is 48.

So 1/4-7/48 = (12*1-7*1)/48.
= 5/48.

Rajesh said:   1 decade ago
Please explain:

1/4-7/48 = 5/48.

5/48 how it comes?

Yasodha said:   1 decade ago
How to came 4/48 explain it?

Raj said:   1 decade ago
Why did write 48/5 is in 5/48?

Kishore said:   1 decade ago
How can we know the that C can do full in (1/how much work 'C ' done in one day) ?

Naim Hussain said:   1 decade ago
For those who can't understand the 5/48 and 48/5 issue, here's my explanation:

C can do 5/48 amount of work in = 1 day.
C can do 1 full work in = 1/5/48 = 48/5 days.

Hope this helps for good.

Soumyajit said:   1 decade ago
If I want to solve this problem in this way,
Suppose C can do this work in X day.
Then, in 1 day A can do 1/16, B can do 1/12, C can do 1/X.
Then, 1/16 + 1/12 + 1/X = 1/4.

Can I solved this answer in this way?

Rekha said:   1 decade ago
How this 9 3/5 is got from 5/48?


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