NCEES (2008 ed) Q103

[Tido]

I undestand that D is a correct answer. But I don't see why A can not be an answer too! Since the activity of D is dependent on B being finished, i.e., connected, the late finish of B is the same as late start of D. Because activity B must be finished before D can start. And the latest B can go is the latest D can wait.

Please convince me otherwise.

thanks for your input

 

[T_McK_PE]

Can you post the entire question? Most of us don't have the new sample exam. I'm sure I can figure out what the problem is.

 

[IlPadrino]

I undestand that D is a correct answer. But I don't see why A can not be an answer too! Since the activity of D is dependent on B being finished, i.e., connected, the late finish of B is the same as late start of D. Because activity B must be finished before D can start. And the latest B can go is the latest D can wait.
Please convince me otherwise.

thanks for your input

You're question is essentially this: Does the LF of B equal the LS of D?

In this network, I agree and you're right that A is a true answer. But if this were the real test, I hope you'd recognize D as the "best" answer.

It looks like there are more than one error in the Sample tests - and there's no errata yet published. Maybe a refund is in order!

 

[T_McK_PE]

You're question is essentially this: Does the LF of B equal the LS of D?
In this network, I agree and you're right that A is a true answer. But if this were the real test, I hope you'd recognize D as the "best" answer.

It looks like there are more than one error in the Sample tests - and there's no errata yet published. Maybe a refund is in order!

Still waiting for someone to post the whole question....

Anyhow, I will agree that with the previous poster in that you need to recognize the BEST answer. As a PE, these are the types of decisions I have to make every day. Luckily, the exam does a pretty good job of separating the "haves" from the "have nots"

 

[owillis28]

Here you go!

owillis

 

[IlPadrino]

owillis28,

Would you also please wash T_McK_PE's car and pick up his laundry for him?

 

[Capt Worley PE]

Even though T_McK_PE is a CE specializing in wastewater modeling (the hardest thing in CE), I suspect he will make short work of your problem.

 

[T_McK_PE]

Even though T_McK_PE is a CE specializing in wastewater modeling (the hardest thing in CE), I suspect he will make short work of your problem.

I will indeed.

Even though Sraymond is a whiny little $%#^@, they are somewhat correct in their previous post. Obviously the best answer is D because all of the elements of answer D are dependent on activity B controlled by activity B. Late start of D is also dependent on C, suckas!

IlPadrino, I like my shirts with extra starch...

 

[kevo_55]

I think wastewater modeling is hard though.

 

[T_McK_PE]

I think wastewater modeling is hard though.

The only wastewater modeling YOU can probably do is your twice-daily trips to the can to purge your bowels.

 

[kevo_55]

^^^ :appl:

 

[BluSkyy]

I'm lost here. If this is the real T McK PE, please tone it down. Its hard to read what you say...

 

[IlPadrino]

I will indeed.
Even though Sraymond is a whiny little $%#^@, they are somewhat correct in their previous post. Obviously the best answer is D because all of the elements of answer D are dependent on activity B controlled by activity B. Late start of D is also dependent on C, suckas!

IlPadrino, I like my shirts with extra starch...

Please share with us the logic that leads you to the conclusion LS of D depends on C? I'll gladly wager a six-pack of beer against your starched shirts that you'll fail to come up with a correct explanation. But, please, do try.

 

[Tido]

Please share with us the logic that leads you to the conclusion LS of D depends on C? I'll gladly wager a six-pack of beer against your starched shirts that you'll fail to come up with a correct explanation. But, please, do try.

Late start of D is dependent on both C and B. But this still doesn't convince me.

Let's put it this way. Activity D cannot start without C AND B finish and the latest will be the LF of either C or B. Whatever it is B can stretch until D starts. That means the float for B will go all the way to the Late start of D no matter who controls ths LS of D. This makes answer A exactly the same as D. There is no best. Both will give you EXACTLY the same number.

 

[IlPadrino]

Late start of D is dependent on both C and B. But this still doesn't convince me.
Let's put it this way. Activity D cannot start without C AND B finish and the latest will be the LF of either C or B. Whatever it is B can stretch until D starts. That means the float for B will go all the way to the Late start of D no matter who controls ths LS of D. This makes answer A exactly the same as D. There is no best. Both will give you EXACTLY the same number.

Do you agree that the backward pass uses the following rule: LF equals the earliest (smallest) LS of all it's immediate successors and LS equals LF minus duration?

Being pedantic, I agree LSs *depend* on whatever happens in the forward pass, so I got sucked into using a poor choice of word (thanks for nothing, T_McK_PE!). Nevertheless, LF of B equals the LS of D in this network, REGARDLESS of anything that happens with C. Activity C can only change the value of D's LS but it cannot change the relationship between the LF of B and the LS of D (they are equal no matter what).

Did I word this explanation more accurately?

 

[IlPadrino]

Please share with us the logic that leads you to the conclusion LS of D depends on C? I'll gladly wager a six-pack of beer against your starched shirts that you'll fail to come up with a correct explanation. But, please, do try.

T_McK_PE,

Maybe you should do Tido's laundry for penance... You are what we call in the testing business a "distractor".

 

[starkman]

Do you agree that the backward pass uses the following rule: LF equals the earliest (smallest) LS of all it's immediate successors and LS equals LF minus duration?
Being pedantic, I agree LSs *depend* on whatever happens in the forward pass, so I got sucked into using a poor choice of word (thanks for nothing, T_McK_PE!). Nevertheless, LF of B equals the LS of D in this network, REGARDLESS of anything that happens with C. Activity C can only change the value of D's LS but it cannot change the relationship between the LF of B and the LS of D (they are equal no matter what).

Did I word this explanation more accurately?

In truth, yes they both answers indicate the same amount of float, since the LF of B must equal the EF and LF of D since D has no float. However, since A and D are the exact same, to BEST show the total float of B it would make sense to choose the equation that only relies on B as opposed to B and D. The answers are the exact same numerically, but the best answer is still choice D. Kind of dumb question in my opinion because of the 2 numerically correct answers, choosing between the two doesnt really test any extra knowledge. I hope they put very few of those on the exam.

 

[T_McK_PE]

Please share with us the logic that leads you to the conclusion LS of D depends on C?

are you serious? see below.

Some people you just can't help.

Good luck on the FE.

 

[Tido]

are you serious? see below.
Some people you just can't help.

Good luck on the FE.

Chill out! The idea of this board is to help one another in our beloved profession. For trash talking there are many places on the net. After all, you just joined. Take time to meet the many great people here.