$$ Assume you are the project manager and based on your customer$$s requirements you have determined there are four main tasks in a Dream Backyard project. Each phase has been assigned a TBC$.$ Specifically, the customer wants a pool and spa built $($Task $1-$ $$50,000)$; all plumbing, electrical, and mechanical installed $($Task $2-$ $$20,000)$; a pool deck with planters and a raised fire pit $($Task $3-$ $$15,000)$; and landscaping and clean up $($Task $4-$ $$5,000).$ You estimate this will take $5$ weeks to complete. The costs are budgeted as follows:

Budgeted Per Week $($in $000$s$)$

TBC $12345$

Task $1501520105$

Task $22061112$

Task $315942$

Task $4523$

What is the total cumulative TBC$?$ What is TBC at the end of week $4?$