i have a question i don't quite understand, i am preparing for a exam.

A 100-gallon mixture of citrus extract and water is 3% citrus extract, and it needs to be diluted. The function f(x)=3/100+x represents the percentrage (in decimal form) of the miture that is citrus extract when x gallons of water are added.
Find the domain of f(x). Then, find the percentage of citrus extract in the mixture after 50 gallons of water are added to it.

Question

i have a question i don't quite understand, i am preparing for a exam.

A 100-gallon mixture of citrus extract and water is 3% citrus extract, and it needs to be diluted.  The function f(x)=3/100+x represents the percentrage (in decimal form) of the miture that is citrus extract when x gallons of water are added.
Find the domain of f(x).  Then, find the percentage of citrus extract in the mixture after 50 gallons of water are added to it.

anonymous · Answer

I assume this is $$f(x)=\frac{3}{100+x}$$
since x is supposed to be water added, then x must be greater than zero.  If you are allowed to take away water then x must be greater than -100.
to find the percentage, replace x by 50 to get 3/150= .02 = 2%