# Schedule, Lead time + contigency. A twisted sum

**URL:** <https://community.blackspectacles.com/t/schedule-lead-time-contigency-a-twisted-sum/6192>\
**Category:** Construction & Evaluation\
**Tags:** practice-quiz\
**Created:** [October 29, 2024, 2:09am UTC](https://community.blackspectacles.com/t/schedule-lead-time-contigency-a-twisted-sum/6192 "2024-10-29T02:09:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ussbea](https://blackspectacles.com/uploads/images/18.png) [@ussbea](https://community.blackspectacles.com/u/ussbea)\
**Post date:** [October 29, 2024, 2:09am UTC](https://community.blackspectacles.com/t/schedule-lead-time-contigency-a-twisted-sum/6192/1 "2024-10-29T02:09:47Z")

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I’m really stuck in the Case Study#2 Question #6 of the randomized exam (Transportation Hub in a Small Rural Town)  
Question ask for the earliest date for install Bike Racks.  
I’m unable to follow the math of the response: If Lead Time, as per RFI is 6 weeks, the activity, per schedule is 6 calendar days, why they are displacing the commencement date only 2 weeks?  
Besides, question #3 in same Case Study displace another activity one week based on the contigency stated in same Schedule (same resource applied to Question #6).  
Why this same condition doesn’t apply in Question #6? Or does, and it is not explained in the response?

Waiting help,  
Thanks in advance.

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**Author:** ![kiaragalicinao](https://yyz1.discourse-cdn.com/flex029/user_avatar/community.blackspectacles.com/kiaragalicinao/32/1607_2.png) [@kiaragalicinao](https://community.blackspectacles.com/u/kiaragalicinao)\
**Post date:** [October 30, 2024, 4:38pm UTC](https://community.blackspectacles.com/t/schedule-lead-time-contigency-a-twisted-sum/6192/2 "2024-10-30T16:38:20Z")

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Hi @ussbea, thank you for your question.

The project schedule reflects bike rack installation only - it does not specify which type of bike rack is being proposed here or what the lead time is. Therefore, we need to determine what effect(s) in-ground bike racks would have on the schedule, if any. Does it align with the proposed installation date or does it push the schedule back?

The RFI indicates that in-ground bike racks have a 6-week lead time (resulting in a schedule change) and surface-mount bike racks have a 4-week lead time (resulting in no schedule change). Therefore, we can assume that the project schedule aligns with using surface-mount. If we use in-mount, the lead time increased by 2 weeks and in turn, pushes the installation back by 2 weeks.

The second question you reference is a different situation, where a 1-week contingency has already been factored into the schedule. Therefore, pushing the start date back by 1 week does not affect the completion date.

Hope this helps!

Kiara Galicinao, AIA, NCARB  
**Black Spectacles**