Question

Food and Drug Administration (FDA) recommends
that adults ingest less than 2.4 g of sodium per day.
How many liters of softened water, containing a
sodium concentration of 0.050% sodium by mass,
have to be consumed to exceed the FDA recommendation?
(Assume a density of 1.0 g/mL for water.)

Answer 1

2.4 = .0005 *(grams of water)
so
grams of water = mL of water = 2.4/.0005
so
liters of water = 2.4/.5 = 4.8 liters