TOPIC: Question on Lead and Lag

The source is PMP Examp Prep by Chris Scordo

The premise of the question is - Building completion has to be preceded by the landscaping and land scaping should start atleast 15 days before building completion. Exact Question is -
Which of the following relationships most likely represents the relationship of the start of landscaping work to the completion of the office building?

A. FS with 15 days Lead
B. SF with 15 days Lead
C FS with 15 days Lag
D. SF with 15 days Lag

Though this is a simple question but i am baffled by the answer a bit
Can you please explain and also why

Paresh,

Please tell us... what is the "official" answer and what do you find surprising about it?

The answer is FS + 15 days lag

i had assumed FS because finish of landscaping before finish of building
But this is a 15 day delay so i had chosen C but the answer is A a 15 day lead

Paresh,

I am just as confused as you are.

Based on the description you gave "Building completion has to be PRECEDED by the landscaping" I would have selected answer "A. FS with 15 days Lead" because FS with a lead makes the second task start earlier.

Have you contacted the original question author and asked for an explanation?

your answer is correct CF..
i was visualizing it incorrectly

i later thought what i would have done in MPP and it made sense

Let us assume Finish Landscaping is 10th task and its a milestone view
(its example not to be considered very specific)

#

---

description----duration---Predecessor

'10' - Finish Landscaping

---

0days --- assume -9FS
'11'- Complete building ---- 0days ----10FS+15 -- thus lead

Suppose the Building Construction work need 40 days. and Land Scaping need 30 days.
In normal process, The building will be completed first within 40 days and then Land Scaping will take 30 days.Total Time will be 40+30=70 days.
But Applying Lead time for Land Scaping...The task will start 15, Total workdays prior and thereby overlap the construction work for 15 days. So, total time will be
40+15(30-15)=55 days. So it is Finish to start 15. That means Building completion task finishes and prior to finish that task Land Scaping start..

Correct answer is A because a “Lead” provides acceleration to the Successor Activity with Finish to Start (FS) relationship. Successor starts 15 days before Predecessor finish.