Freight car loadings over an 18week period at a busy port are as follows: 
Week 
Number 
Week 
Number 
Week 
Number 
1 
410 
7 
460 
13 
540 
2 
420 
8 
480 
14 
550 
3 
430 
9 
500 
15 
570 
4 
420 
10 
490 
16 
580 
5 
430 
11 
510 
17 
590 
6 
440 
12 
530 
18 
600 

a. 
Determine a linear trend line for expected freight car loadings. (Round your intermediate calculations and final answers to 2 decimal places.) 
= [removed] + [removed] t 
b. 
Use the above trend equation to predict expected loadings for Weeks 20 & 21. (Round your final answers to 2 decimal places.) 

The forecasted demand for Week 20 is [removed] and for Week 21 is [removed] . 
c. 
The manager intends to install new equipment when the volume exceeds 990 loadings per week. Assuming the current trend continues, in which week (at the earliest) should the loading volume reach that level? (Use the rounded answers, as required, from any previous part of this problem. Do not round any other intermediate calculations. Round your final answer to 2 decimal places.) 
It should reach 990 loadings in Week [removed] . 