Final answer:
To calculate labor costs for custom-designed wheelchairs in cell B21, use the formula =B5*F5*B11, which can then be copied to other cells to calculate various costs. Use relative cell referencing to ensure the formula adjusts appropriately when copied.
Step-by-step explanation:
To calculate the costs of labor for custom-designed wheelchairs in cell B21, you would use the following formula:
=B5*F5*B11
This formula multiplies the hourly rate in cell B5 by the number of hours required to create a custom wheelchair from cell F5 by the number of custom wheelchairs produced from cell B11. To ensure that this formula can be copied across and down the spreadsheet without issue, make sure to use relative cell referencing since the question implies that the cell references will change depending on the position to which the formula is copied.
By following this approach, you can calculate not only the labor costs but also the costs of primary and additional materials by copying the formula down to cells B22 and B23, and you can also adjust this formula to calculate all costs for standard wheelchairs by changing the cell references accordingly.