Elitmus
Exam
Numerical Ability
Time and Work
A,B and C can do a piece of work in 12,18, and 24 days respectively. they work at it together . A stops the work after 4 days and B is called off 2 days before the work is done.In what time was the work finished?
Read Solution (Total 8)
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- If A can do a piece of work in 12 days then in one day he can do 1/12 work.
Similarly, B's one day work is 1/18
and C's one day work is 1/24.
Here it tells about the no of days A and B worked but its not telling anything about C.
So, lets assume C work for x days.
then, B work for x-2 days(as it given that he left the job 2 days before completion)
and, A work for 4 days(as given in the question)
Therefore, A's work + B's work + C's Work = 1
4/12 + x-2/18 + x/24 = 1
After solving,
x = 8 days.
Therefore, we assumed that C worked for x days means C is the only one who worked till the last day. Therefore x=8 is the required answer.
Therefore, the total work was finished in 8 days. - 10 years agoHelpfull: Yes(62) No(3)
- percentage of work done by A=(1/12)*100=8.33%
similarly B=5.55%
C=4.16%
WORK DONE IN 4 DAYS=4(8.33+5.55+4.16)=72.16% (APPROX)
WORK DONE BY C ALONE IN LAST 2 DAYS=2*4.16=8.32%
WORK LEFT TO BE DONE=100-72.16-8.32=19.52%
THIS IS TO BE DONE BY BOTH B AND C SO NO OF DAYS REQUIRED=
19.52/(5.55+4.16)=2 DAYS(APPROX)
HENCE TOTAL DAYS= 4(DONE BY ALL)+2(DONE BY B AND C)+2(C ALONE)=8DAYS
- 10 years agoHelpfull: Yes(12) No(1)
- ans:-8 days
A's work - 1/12
B's work - 1/18
C's work - 1/24
all of them worked at it for 4 days so total work:-
4(1/12+1/18+1/24)=26/36
now,
remaining work is 1-(26/36)=5/18
Now suppose that both B and C take 'x' days to complete a work of 5/18
(It is given that B is called off 2 days before the work is done)
thus,
(x-2)/18+(x/24)=5/18
solving we get x=4
So,
(B and C worked at it for 2 days followed by 2 days work of C alone)
to these 4 days we add previous 4 days of working of all of them together...
Thus
4 days (A+B+C) + 4 days((2 days B+C) + 2 days of C alone) = 8 days..
8 days - 10 years agoHelpfull: Yes(10) No(0)
- A work 4/12 in 4 days=1/3
so left work =2/3.
now let work is completed in x days then,
(x-2)/18+x/24=2/3.
x=8.
- 10 years agoHelpfull: Yes(7) No(0)
- 8 days(4+2+2)
- 10 years agoHelpfull: Yes(3) No(4)
- A---12
B---18
C---24
LCM of these 3 is 72
units of work done by A----6
units of work done by A----4
units of work done by A----3
NOW, 6+4+3=13
they all worked together 4 days in the starting so 13*4=52
so work remaining after 4 days=72-52=20
means 20units of work is remaining
now B left before 2 days so total unit of work remaing will become (4*2)+20=28
so no. of days=28/(4+3)=4 days
and the days they worked together=4 days
so total days=4+4=8 days - 10 years agoHelpfull: Yes(2) No(0)
- 4 days (A+B+C) + 4 days((2 days B+C) + 2 days of C alone) = 8 days.
- 10 years agoHelpfull: Yes(1) No(0)
- 8 days
Total work-72
A-12(6)
B-18(4)
C-(3)
A+B+C=(6+4+3) *4=52(for 4 days)
Then remaining work 72-52=20
B left the work 2 days before done
That means C works alone 2 days
2*3=6
Then remain work=20-6=14
14 work done by B+C=14/2=7
That is total days =4+2+2=8 - 3 years agoHelpfull: Yes(0) No(0)
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