Freight car loadings over an 18-week period at a busy port are as follows:

1.Week Number Week Number Week Number

1 220 7 350 13 454

2 245 8 360 14 475

3 278 9 439 15 490

4 275 10 380 16 510

5 302 11 450 17 549

6 310 12 450 18 541

a. Determine a linear trend line for expected freight car loadings. (Round your intermediate calculations and final answers to 3 decimal places.)

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b. Use the trend equation to predict expected loadings for weeks 23 and 24. (Round your intermediate calculations and final answers to 3 decimal places.)

The forecasted demand for week 23 is _______ and 24 ________ respectively.

c. The manager intends to install new equipment when the volume exceeds 845 loadings per week. Assuming the current trend continues, the loading volume will reach that level in approximately how many more weeks? (Round your intermediate calculations to 3 decimal places and final answer to the nearest whole number.)