Hmm, one way is this there's 500 times 0.10 or 50 grams of salt in the water if we want to make 50 grams=4% of everything, how much water do we need to add
50=4% of all 50=0.04 of all divide both sides by 0.04 1250=all so 500+what=1250 minus 500 both sides what=750