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:
226 comments Page 11 of 23.

Onkar Vitthal Dabhole said:   1 decade ago
A very very simple solution than the provided as above.

A can complete a work in 16 days, B can complete the same work in 12 days and with the help of C together if they complete the work in 4 days, so assume total work to be done is 48. (LCM of 16, 12, 4).

Persons A B C | A+B+C.

Days- 16 12x = (48/5) = (9+3/5)4.

Work/day- 3 4 5 12 = 3+4+C.

Hence C = 5.

----------------------------------------------------------------.

Work - 48 48 48 48.

Sagar said:   1 decade ago
Anyone explain me what is 5 and 48 in relation to C?

Tamilmani said:   1 decade ago
Please answer sir basic formula applied please.

Lijin said:   1 decade ago
How it possible to write 5/48 to 48/5?

See A can complete a work in n days.

A's 1 day work = 1/n.

So here 1/n = 5/48.

So n = 48/5.

Got it!

Khizer said:   1 decade ago
= 1/16+1/12+1/C = 1/4.

C = 48/5.

Naresh saini said:   1 decade ago
How it is possible to write 5/48 to 48/5?

Bhavana said:   1 decade ago
Firstly take the LCM.

A B ABC.
16 12 4.

LCM IS 48 then ratio is.

A B ABC.
3 4 12.

If a+b-ABC then it's find the value of C = 5 total is 48.

Then divide the 48/5 so simple.

Helper said:   1 decade ago
We get 1/x=5/48.

Then we want x. So x=48/5.

Shivu said:   1 decade ago
Hi thanks all of you solving this problem in easy methods.

Adusumalli prasanna said:   1 decade ago
a+b+c=1/4 a's 1st day work = 1/16 b's 1st day work = 1/12.

Therefore c's 1 day work = 1/4-{1/16+1/12) after that 1/4-(12+16/192) {by doing LCM) by dividing 28/192 (by multiplying 2nd table) then we get 1/4-7/48 (by doing LCM).

We get (48-28/192) = 20/192 = 10/96 (dividing with 2 table) we get 5/48. Now please help me why we are taking as 48/5.

Whats the reason explain me clearly please?


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