Final answer:
The student's question involves using the Excel COUNTIF function to determine quantities of hot tub models, applying mixed references, and ensuring cell formatting and borders are maintained after copying the formula.
Step-by-step explanation:
The student is asking how to use the COUNTIF function in Excel to calculate the quantity of each hot tub model. You will insert the function in cell C15 with mixed references for the range and a relative reference to the first model in cell A15. Then, you'll copy the function down to C16:C17, ensuring that the border in C17 remains unchanged. It is important to apply Center horizontal alignment to the cells where the function has been inserted.