Explainations: Calculate Cost

Step 1

If you haven't already, put the slope and y-intercept of your trendline in the table. Don't forget to copy their sign!

Step 2

Remember, the trendline and its equation represent how many milligrams of CaCO3 is needed to reach the desired pH in 100mL of water. So write a formula in cell D12 that will use your equation to calculate how much CaCO3 you need to reach the pH given in cell D11.

Step 3

For the next two slots, use your knowledge of the metric system to write formulas that will convert the value you calculated in cell D11 into the units asked for.

Step 4

Use the value for "Cubic feet of flow per second" and the conversion factor given to write a formula that will find "Liters of flow per second". Then use the conversion factor to convert that value into "Liters of Flow per year".

Step 5

Now, use the value you calculated in D14 and the value you just calculated in D19 to find how much CaCO3 you need per year.

Step 6

Use your knowledge of the metric system to determine how much 1kg of CaCO3 costs based on the cost of 100kg.

Step 7

Finally, use the value in D20 to write a formula that will calculate how much enough CaCO3 to naturalize the river will cost each year.