A town requiring 2.0 m3/s of drinking water has two sources, a local well with 15 g/m3 nitrate (as N) and a distant reservoir with 5 g/m3 nitrate (as N). What flow rates of well and reservoir water are needed to meet the EPA drinking water standard and minimize the use of more expensive reservoir water

Explanation:

Drinking water requirement in town 2.0 m^3/s of water per second

nitrate in local well  nitrate per 15 of water

nitrate in distant reservoir

Let the flow rate of well

flow rate of reservoir

Drinking water requirement is or

therefore, the total flow of drinking water

real, smaller and upside-down.   so the answer should be b.

overcharge is the right answer system