We have been given that Sterre charges $35 to file tax returns, but files for free if she only needs the easiest form. Also, she donates $2 to clean water projects per tax return she files.
Further we know that Sterre charged $7,245 and made a donation of $1,242 this year for the tax returns she filed.
Let x be the number of free income tax returns and y be the number of $35 income tax returns.
Therefore, we can set up:

Since she donates $2 for each return that she files, therefore, we can set up:

Therefore,
Sterre filed 414 tax returns for free and filed 207 tax returns for $35.
It should be 2 to 3, so the last answer should be right
Answer: 376.98192 mL
Step-by-step explanation:
We are going to use this equation.
V = π * r² * h
according to the question we have the value for r and h, if you replace the values into the equation we will get following product:
note: also keep in mind that value of π is 3.141516
V = π * r² * h
V = π * (4in)² * (10in)
V = 502.64256 in³
after we can divide this value in 4 equals parts
then we get the following equation:
502.64256 in³ / 4 = 125.66064 in³
after that that you can multiply this value by 3 to get the 3 parts of the cylinder vase for example:
125.66064 in³ * 3 = 376.98192 in³
and this result is the volume of water that we have to pour into the vase