Aptitude - Time and Work - Discussion

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"I never see what has been done; I only see what remains to be done."

- Marie Curie

19.

A, B and C can complete a piece of work in 24, 6 and 12 days respectively. Working together, they will complete the same work in:

[A].

1	day
24

[B].

7	day
24

[C].

3	3	days
	7

[D].

4 days

Answer: Option B

Explanation:

Formula: If A can do a piece of work in n days, then A's 1 day's work = 1 .

n

(A + B + C)'s 1 day's work = 1 + 1 + 1 = 7 .

24 6 12 24

Formula: If A's 1 day's work =	1	,	then A can finish the work in n days.
	n

So, all the three together will complete the job in 24 days = 3 3 days.

7 7

Baskar said: (Sat, Jun 5, 2010 09:16:04 PM)

First you multiply 3 and denominator (37=21) and that coming answer add with numerator (21+3=24) then finally that answer divide by denominator (24/7=33/7)

Mansi said: (Sun, Jun 6, 2010 02:42:52 AM)

Front value multiplied by dr. and added to nr value for example 7*3=21 is added to nr value 21+3=24 hence 24/7 You can make the answere in nr/dr form and compare better thn converting in othr form

Sanjukta Nayak said: (Mon, Jun 28, 2010 04:24:53 AM)

Me confused,please help

Muthukumar said: (Tue, Jun 29, 2010 03:55:43 AM)

I am not understand how to you got 7/24.

Mohit said: (Sun, Jul 18, 2010 09:03:48 AM)

Hey look at the question first he is asking days for completion of work so If A's 1 day's work = 1/n then A can finish the work in n days its reciprocal of it.

Dharma said: (Fri, Oct 22, 2010 02:18:29 AM)

A's work be x, B's work be y C's work be z Total work done by A,B,C(A+B+C)=(XYZ)/(XY+YZ+XZ) Solution is: x=12 y=6 z=24 A+B+C=(12624)/(126+624+24*12) = 24/7 = 3 and (3/7)

Aditya said: (Wed, Feb 9, 2011 08:47:22 AM)

Thank you dharma you helped me alot.

Swetha said: (Tue, Aug 9, 2011 04:43:08 PM)

Given: A can do a work in 24 days B can do a work in 6 days C can do a work in 12 days Take LCM for 24,6 & 12 i.e 24 total work = 24 A's per day capacity = 24/24 = 1 B's per day capacity = 24/6 = 4 C's per day capacity = 24/12 = 2 If all working together, their per day capacity = 1+4+2 = 7 all together will complete the work in 24/7 = 3 3/7 days

Dopeboy said: (Wed, Oct 12, 2011 12:47:02 PM)

If the work done by A is n , then the work done is one day is 1/n. Similar to (1 part of the work)/complete work. Total work done together in one day is : 1/n = 1/12+1/24+1/6= 7/24 Total work done together : n = 24/7.