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# Working alone Jerry can complete a work in 6 minutes. Working alone, A

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Joined: 02 Sep 2009
Posts: 65761
Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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03 Dec 2018, 03:14
00:00

Difficulty:

35% (medium)

Question Stats:

75% (01:57) correct 25% (02:20) wrong based on 178 sessions

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Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

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Re: Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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03 Dec 2018, 03:19
3
LCM of 6 and 8 is 24 units = Total work to be done.
Jerry can do 4 units per minute.
Adam can do 3 units per minute.
Working together they complete 7 unit per minute.

Working for 2 minute they complete 14 units. Pending is 24-14 = 10 units.
Adam will complete in 10/3 minutes.

Posted from my mobile device
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Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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Updated on: 04 Dec 2018, 23:18
Bunuel wrote:
Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

GMATinsight :

Sir, I solved the question using below method , but I am not able to get option C which is correct answer ...

Rate of jerry = x/6 and rate of Adam= x/8
combined rate : x/6+x/8 = 7x/24 and work would be x.24/7
work done in 2 mins: x.(7/24) * 2 = 7x/12
work left =x - 7x/12 = 5x/12
time Adam will take : work = rate * time
5x/12=x/8* time

time : 10/3 IMO C

Originally posted by Archit3110 on 03 Dec 2018, 03:59.
Last edited by Archit3110 on 04 Dec 2018, 23:18, edited 1 time in total.
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Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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04 Dec 2018, 09:21
1
Archit3110 wrote:
Bunuel wrote:
Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

GMATinsight :

Sir, I solved the question using below method , but I am not able to get option C which is correct answer ...

Rate of jerry = x/6 and rate of Adam= x/8
combined rate : x/6+x/8 = 7x/24 and work would be x.24/7
work done in 2 mins: x.(7/24) * 2 = 7x/12
work left = x.24/7 - 7x/12 = x.(239/84)
==> Work Left= 1-(7/12) = 5X/12

time Adam will take : work = rate * time
x.(239/84)=x/8* time
I am doing something wrong ... I am not sure what and where please check...

==> Adam takes 8 min / work . So , 5X/12 work is done in ==> 5(8)/12 = 10/3
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Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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04 Dec 2018, 23:17

wrote:
Archit3110 wrote:
Bunuel wrote:
Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

GMATinsight :

Sir, I solved the question using below method , but I am not able to get option C which is correct answer ...

Rate of jerry = x/6 and rate of Adam= x/8
combined rate : x/6+x/8 = 7x/24 and work would be x.24/7
work done in 2 mins: x.(7/24) * 2 = 7x/12
work left = x.24/7 - 7x/12 = x.(239/84)
==> Work Left= 1-(7/12) = 5X/12

time Adam will take : work = rate * time
x.(239/84)=x/8* time
I am doing something wrong ... I am not sure what and where please check...

==> Adam takes 8 min / work . So , 5X/12 work is done in ==> 5(8)/12 = 10/3

baru thanks a lot .. such a stupid error i did in the end ... .. thanks for highlighting the error..
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Re: Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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07 Dec 2018, 02:47
Archit3110 wrote:
Bunuel wrote:
Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

GMATinsight :

Sir, I solved the question using below method , but I am not able to get option C which is correct answer ...

Rate of jerry = x/6 and rate of Adam= x/8
combined rate : x/6+x/8 = 7x/24 and work would be x.24/7
work done in 2 mins: x.(7/24) * 2 = 7x/12
work left =x - 7x/12 = 5x/12
time Adam will take : work = rate * time
5x/12=x/8* time

time : 10/3 IMO C

This question can be solved in two ways

Method 1:
Jerry's 1 minute work = 1/6
Adam's 1 minute work = 1/8

Work done by Jerry in 2 minutes = 2/6 = 1/3
Remaining work = 1 - (1/3) = 2/3

Adam can finish (1/8) work in 1 minute
Adam will finish (2/3) work in (2/3)*8 = 16/3 minutes

Additional time for which Adam worked alone = 16/3 - 2 - 10/3

Method 2

Let work = LCM of 8 and 6 = 24 units

Jerry's 1 minute work = 24/6 = 4 units
Adam's 1 minute work = 24/8 = 3 units

Jerry's work done in 2 minutes = 2*4 = 8 units

Remaining work = 24 - 8 = 16 units

Time taken by Adam to finish 16 unit work = 16/3 minutes

Extra time that Adam worked alone for = 16/3 - 2 = 10/3 minutes

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Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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08 Dec 2018, 10:25
Bunuel wrote:
Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

Another way, not hard: two stages. Use combined rate in the first stage.
J's rate: $$\frac{1}{6}$$
A's rate: $$\frac{1}{8}$$
Combined rate$$_{(J+A)}$$:$$(\frac{1}{6}+\frac{1}{8})=\frac{14}{48}=\frac{7}{24}$$

They work together for 2 minutes. Then Jerry leaves.

(1) Stage 1: Work completed together?
$$R_{(J+A)}*T_{mins}=W$$
$$(\frac{7}{24}*2)=\frac{14}{24}W=\frac{7}{12}W$$

Together they finish $$\frac{7}{12}$$ of work. Job = 1
So the work remaining for Adam is
$$(1-\frac{7}{12})=(\frac{12}{12}-\frac{7}{12})=\frac{5}{12}W$$

(2) Stage 2: Time required for Adam to finish the work?
$$R_{A}*T_{mins}=W_{remaining}$$

$$\frac{1}{8}*T_{mins}=\frac{5}{12}$$

$$T_{mins}=(\frac{5}{12}*\frac{8}{1})=\frac{40}{12}=\frac{10}{3}$$ minutes*

*In solving for $$T$$ by clearing LHS, the underlying operation is just $$T=\frac{W}{R}$$, thus:
$$\frac{1}{8}*T_{mins}=\frac{5}{12}$$
$$T_{minutes}=\frac{W}{R_{A}}=\frac{(\frac{5}{12})}{(\frac{1}{8})}=(\frac{5}{12}*\frac{8}{1})=\frac{40}{12}=\frac{10}{3}$$

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Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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15 Dec 2018, 05:11
Bunuel wrote:
Working alone Jerry can complete a work in 6 minutes. Working alone, Adam can complete a work in 8 minutes. Working together, Jerry leaves the work after 2 minutes. How long will it take Adam to complete the work?

A. 2 minutes
B. 3 minutes
C. 10/3 minutes
D. 5 minutes
E. 10 minutes

All the above solutions are helpful and should be solved in that way when YOU HAVE TIME...
when you are running out of time...US THIS
i used the answer choices to increase my probability of answering the question right
we are given individual rates ... Rate of jerry > rate of adam
working alone adam complete the ENTIRE work in 8 minutes os with the help of jerry he will complete it in even less time
option E is gone

as we know rate of j > rate of adam and jerry works for 2 minutes and then leaves then for the rest of the part adam has to work...as adam is slower than jerry it is impossible for him to complete the remaining job in 2 mins
option A is gone

we have 6 and 8 in the question... 6 is a multiple of 2 and 3 ... division by 3 of a non multple of three ends in a non terminating decimal ...so the adddition and interpolation of fraction ending up in integer value when reversed for time is very less

this eliminate B and D...
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Re: Working alone Jerry can complete a work in 6 minutes. Working alone, A  [#permalink]

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20 Jun 2020, 04:03
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Re: Working alone Jerry can complete a work in 6 minutes. Working alone, A   [#permalink] 20 Jun 2020, 04:03