chemistry
posted by greg .
A 375 g sample of well water is found to contain 17.0 mg of lead. How much lead (in parts per million) is in the well water? Round to the nearest tenth. Don't forget the unit.

ok, lets go to millions...
in 375million, there ware 17(milli x million) or 17,000 grams of lead.
17,000/375,000,000 parts per million or
17/375,000 or hhhhhmmmmmm. Round to the nearest tenth? so is it 45.3 ppm ? 
35.63