What is the duration of this activity?

Submitted by Jp2786 on Tue, 05/27/2014 - 03:18

1.       An activity has an early start,(ES) of day 13,an early finish (EF) of day 9 and a late finish (LF) of day 19. What is the duration of this activity?

A 3

B 6

C 7

D 10

I'm guessing there is typo in the question how can ES be 13 and EF be only 9?

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sunku65

Tue, 05/27/2014 - 13:25

Its not typo.

They want make confuse us.  They ask only duration na, simple do LF-LS

i.e 10

keyveeyen

Tue, 05/27/2014 - 17:57

There is no LF..only LS is given. 

based on the question .. the duration is -4 (EF-ES) 

but the answer is not available ?? 

sunku65

Wed, 05/28/2014 - 14:31

typo also in my reply.

They want make confuse us.    They asl only duration na, simple LF-LS or EF-ES.

i.e 6  ( 10 is the float)

keyveeyen

Tue, 05/27/2014 - 18:02

<p>LF-EF / LS-ES is free float formula.. Whereas EF-ES is the duration formula.&nbsp;</p><p>&nbsp;</p><p>please correct me if iam wrong.&nbsp;</p><p>&nbsp;</p>

keyveeyen

Tue, 05/27/2014 - 18:03

LF-EF / LS-ES is free float formula.. Whereas EF-ES is the duration formula. 

please correct me if iam wrong. 

 

keyveeyen

Tue, 05/27/2014 - 18:05

Jp2786

Tue, 05/27/2014 - 18:32

Yes keyveeyen  equations are correct.

LS-ES or LF-EF give the float of the activitity

EF-ES or LF-LS give the duration of the activity

As per the given values float is 10 and duration is -4 (How can -4 be the duration of an activity?)

 

 

sunku65

Wed, 05/28/2014 - 14:56

@JP2786

While cut and paste somebody missed some information somewhere in some website.  Thats why this mistake may conitues for one website onother one.   I searched in the google.  I found this information.  I concludes that the right version of the question may be as follows:

 

An activity has an early start (ES) of day 3, a late start (LS) of day 13, an early finish (EF) of day 9, and a late finish (LF) of day 19. What is the duration of this activity?

a. 3
b. 6
c. 7
d. 10

Here answer is C. 7 days.

Jp2786

Wed, 05/28/2014 - 14:59

Looks like thats the correct version. Thanks for posting.

keyveeyen

Thu, 05/29/2014 - 13:34

Hi Guys,

As per the above Q : EF-ES or LF-LS = 6. So B should be right one.
How come 7 is Right Answer. Please Clarify.

sunku65

Thu, 05/29/2014 - 16:48

ES=3 and EF=9

Duration of days = 3,4,5,6,7,8,9 = Seven days
Duration Formula = EF-ES+1

of day 3, a late start (LS) of day 13, an early finish (EF) of day 9, and a late finish (LF) of day 19. What is the duration of this activity?

a. 3
b. 6
c. 7
d. 10
Here answer is C. 7 days.

sunku65

Thu, 05/29/2014 - 16:56

@typo

ES=3 and EF=9 Duration of days = 3,4,5,6,7,8,9 = Seven days Duration
Formula = EF-ES+1

keyveeyen

Thu, 05/29/2014 - 18:03

Thanks Sunku65 for the clarification.

Nabs

Sun, 06/01/2014 - 12:33

why do duration formula is sometime calculated as
duration = ES- EF

and sometime as
duration = ES- EF+1

Please explain.when do we prefer which formula.

sunku65

Mon, 06/02/2014 - 15:23

Its for our convenience:
Some times network diagram starts with ES=0 or ES=1

Example: A=3 days; B=5 days; C=2days
Path = Start-A(FS)-B(FS)-C(FS)-End
Duration = 3+5+2 =10 days

RITA follows below method :

First activity(A) successor of Start :
ES=0
EF =ES Duration=0+3= 3.

Activity B:
ES =Predecessor Activity A's EF becomes successor activity ES. ie. ES=3.
EF=ES Duration = 3+5=8

Activity C:
ES =Predecessor Activity B's EF becomes successor activity ES. ie. ES=8..
EF=ES Duration = 8+2=10

WE follows below method :

First activity(A) successor of Start :
ES=1
EF =ES Duration-1=1+3-1= 3.

Activity B:
ES =Next day of Predecessor Activity A EF becomes successor activity ES; i.e. ES = 4
EF=ES Duration-1 = 4+5-1=8

Activity C:
ES =Next day of Predecessor Activity B EF becomes successor activity ES;
i.e ES=9.
EF=ES Duration-1 = 9+2-1=10

Depending on given network diagram.
If network diagram starts with 0 as ES, then apply 1st one.
else network diagram starts with 1 as ES, then apply 2nd one

If anything wrong correct me.
Thanks,
Lax

sunku65

Mon, 06/02/2014 - 15:39

see my linkdin posting

https://www.linkedin.com/groups/If-you-are-weak-in-2356441.S.58775172588...

pmalik

Mon, 03/12/2018 - 07:16

You can answer the question yourself by reading this article -
https://www.pmbypm.com/critical-path-analysis-example-0-method-1-method/